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					symmetry
                                      dimensions   volume 06
                                      of
                                      particle
                                      physics



  A joint Fermilab/SLAC publication




                                                   issue 04




                                                   august 09
  volume 06 | issue 04 | august 09




symmetry
  A joint Fermilab/SLAC publication
                                                                                                                   Photo: Kevin Kennefick
2    Editorial: From Technology to Dance
     This issue shows how broadly particle physics pervades other aspects of life—from accelerator technology
     and its many practical applications to interpretations of the science through Manga and choreography.

3    Commentary: Youhei Morita
    “One of these days, I may have to shout at my kids, ‘Manga demo yonde benkyo shinasai!’—study
     hard by reading Manga!”

4    Signal to Background
     Learn physics from evil slugs; South Pole researchers with the right stuff; the butterfly hunter; no dirty
     SNO in Canada; if you can’t make it, send your avatar; letters; correction.

8    symmetry breaking
     A summary of recent stories published online in symmetry breaking, www.symmetrymagazine.org/breaking


10 Superconducting Technology, Chicago Style
   Fermilab is cooking up a hot technology—and the serving is ultracold. The laboratory is stepping up
   efforts to develop and test superconducting radio-frequency cavities, a key technology for the next
   generation of particle accelerators and the future of particle physics.

18 Not a Moment to Lose at the LHC
   Physicists from the Large Hadron Collider’s experiments turn an unexpected shutdown to their advantage.

24 Dancing With Physicists
   For her latest work, choreographer Liz Lerman took members of her dance troupe to CERN, where they
   reveled in the fog, danced in the aisles and found inspiration in wide-ranging conversations with scientists.


30 Gallery: Takuya Uruno
   Bam! Sproing! Gyaaa! In the Web series Kasoku Kids, a Manga artist delivers particle physics with feeling.

34 Day in the Life: Hitoshi Murayama
   “When the Emperor approached me, he stared at my name-tag. He then asked me what I did. I told
    him that I am trying to attack the mysteries of the universe, and am building a new international research
    institute. He wished me good luck.”

38 Accelerator Applications: Heart Valves
   Physicists at Alabama A&M University hope to improve the safety of artificial heart valves by forming
   them from material bombarded with silver ions from a particle accelerator.

C3 Logbook: Weak Neutral Current
   The Gargamelle collaboration at the European laboratory CERN began operating its bubble
   chamber in the early 1970s. This picture, taken in 1972, caught the attention of scientists of the analysis
   group in Aachen, Germany.

C4 Explain it in 60 Seconds: Cherenkov Light
   Cherenkov light appears when a charged particle travels through matter faster than light can. This
   effect is the optical equivalent of a sonic boom.


     On the cover
     Manga artist Takuya Uruno, whose work is featured in the gallery on page 30, designed this issue’s
     cover based on an edutainment Web series he created for KEK. It incorporates, from top,
     a superconducting radio-frequency cavity (see story on page 10); string theory; and a Van de Graaff
     generator, whose static electricity fluffs up the hair of the girl in the middle.

     Inside cover
     Dancers from the Liz Lerman Dance Exchange perform in Ferocious Beauty: Genome. Troupe members
     visited CERN to find inspiration for a new dance piece, tentatively called Matter of Origins. See
     story on page 24.
from the editor

                                 From technology                                            America’s Future” will take place in Washington,
                                 to dance                                                   DC, with sessions addressing medicine and biology,
                                                                                            energy and environment, national security, indus-
                                                                                            trial applications and production, and scientific dis-
                                 Symmetry often discusses the connections                   covery. We’ll bring you coverage of that meeting
                                 between particle physics and other parts                   online at symmetrymagazine.org.
                                 of science, nature, and culture. This issue shows               As examples of the interplay between particle
                                 how broadly particle physics pervades other                physics and culture, we feature in this issue
                                 aspects of life.                                           several stories on physics in Manga, the primarily
                                     The primary justification for doing particle           Japanese form of comics. A leading Manga
                                 physics is the science itself; but along with its          artist, Takuya Uruno, drew our cover; Youhei Morita
                                 discoveries we see the development of many                 from KEK in Japan writes about the influence
                                 technologies crucial for advancing other areas             of Manga in his life and education (page 3); and
                                 of science. Superconducting radio-frequency                we show a gallery of Uruno’s Manga drawings,
                                 acceleration technology (page 10) is one key               commissioned by KEK to help communicate parti-
 Photo: Reidar Hahn, Fermilab




                                 example. Designed for high-energy particle                 cle physics to different audiences (page 30).
                                 collider experiments, it has uses in X-ray sources,             A very different form of science communication
                                 medical accelerators, and myriad other                     is being explored by well-known choreographer
                                 accelerator applications.                                  Liz Lerman. Members of her dance troupe visited
                                     In this issue of symmetry we start a new               the European particle physics laboratory CERN
                                 series about applications of accelerators with the         to develop a performance, attracting curious
                                                             story of how they’re           onlookers as the dancers explored the unusual
                                                             being used to implant          physical space of the Large Hadron Collider and
                                                             silver ions into carbon        its surroundings. Lerman speaks with symmetry
                                                             heart valves to try to         about her collaboration with physicist Gordy Kane,
                                                             make them more bio-            how she learned about the science at CERN,
                                                             logically compatible           and how she began to find new ways to express
                                                             (page 38). It’s just one       those concepts within her field of expertise
                                                             instance in which              (page 24).
                                                             accelerators are playing            Particle physics is done for the sake of scien-
                                                             significant roles in           tific discovery, but the field shows its value to
                                                             science, technology            society not only through its discoveries but also
                                                             and industry.                  through the wide-ranging connections to other
                                                                 On October 26,             human endeavors. It’s a dynamic and vibrant set
                                                             a symposium                    of connections that benefits everybody involved.
                                                             on “Accelerators for           David Harris, Editor-in-chief


                                 Symmetry                          Editor-in-Chief          Publishers                      Print Design and Production
                                                                                                                                                          symmetry | volume 06 | issue 04 | august 09



                                 PO Box 500                        David Harris             Rob Brown, SLAC                 Sandbox Studio
                                 MS 206                            650 926 8580             Judy Jackson, FNAL              Chicago, Illinois
                                 Batavia Illinois 60510            Deputy Editor                                            Art Director
                                 USA                               Glennda Chui             Contributing Editors            Michael Branigan
                                 630 840 3351 telephone                                     Roberta Antolini, LNGS
                                 630 840 8780 fax                  Managing Editor          Peter Barratt, STFC             Designer
                                 mail@symmetrymagazine.org         Kurt Riesselmann         Romeo Bassoli, INFN             Andrea Butson

                                 For subscription services go to   Senior Editor            Stefano Bianco, LNF             Illustrator
                                 www.symmetrymagazine.org          Tona Kunz                Kandice Carter, JLab            Aaron Grant
                                                                   Staff Writers            Lynn Yarris, LBNL               Web Design and Production
                                 symmetry (ISSN 1931-8367)                                  James Gillies, CERN
                                 is published six times per        Elizabeth Clements                                       Xeno Media
                                                                   Calla Cofield            Silvia Giromini, LNF            Oakbrook Terrace, Illinois
                                 year by Fermi National                                     Youhei Morita, KEK
                                 Accelerator Laboratory and        Kathryn Grim                                             Web Architect
                                                                   Kelen Tuttle             Tim Meyer, TRIUMF
                                 SLAC National Accelerator                                  Perrine Royole-Degieux, IN2P3   Kevin Munday
                                 Laboratory, funded by the         Rhianna Wisniewski
                                                                                            Yuri Ryabov, IHEP Protvino      Web Design
                                 US Department of Energy           Interns                  Yves Sacquin, CEA-Saclay        Karen Acklin
                                 Office of Science. (c) 2009       Nicholas Bock            Kendra Snyder, BNL              Justin Dauer
                                 symmetry All rights reserved      Rachel Carr              Boris Starchenko, JINR          Alex Tarasiewicz
                                                                   Tia Jones                Maury Tigner, LEPP              Web Programmer



                                symmetry
                                                                   Lauren Schenkman         Ute Wilhelmsen, DESY            Mike Acklin
                                                                                            Tongzhou Xu, IHEP Beijing
                                                                                            Gabby Zegers, NIKHEF            Photographic Services
                                                                                                                            Fermilab Visual Media
                                                                                                                            Services



                                                                                        2
commentary: youhei morita

   Raised on Manga                                            corporate Manga
                                                              works, establishing it
   When I was a kid, I used to watch animations on            as a business.
   TV and read Manga magazines a lot. As you can                  Uruno becomes
   imagine, my parents were not very enthusiastic             serious when he tries to
   about it at all. “Benkyo shinasai!” meaning “Study         understand the needs
   hard (rather than wasting time on such things)!”           and the backgrounds
   was their automatic, second-nature scolding.               of his clients. His job
   In fact, there were a whole lot of themes in those         starts with choosing
   Mangas, ranging from entertainment to love,                the right corporate
   life, art, history, geography, adventures, comedy,         images and characters
   and tragedy. Kids of our generation were raised            for his work, and he
   in Manga culture, absorbing lots of lessons in these       also reads a lot of doc-
   artificial mini-theaters.                                  uments and back-
       Decades have passed, and Japanese Manga                ground materials
   culture is gradually spreading to the world.               about the clients. We




                                                                                                                             Photo courtesy of Youhei Morita
   Dragonball and Pokemon are becoming popular                have spent almost one year discussing the
   among younger generations of Europeans and                 designs and plots of the new Manga edutain-
   Americans. Still, Western journalists in Japan             ment for KEK. During this period, KEK
   sometimes are amused to see Japanese adults                Professor Makoto Kobayashi shared the Nobel
   so absorbed in reading Manga magazines on                  Prize in Physics, and we discussed how to incor-
   commuter trains. Lots of serious textbooks for             porate this big news into the story.
   training company recruits in economics, law,                   The first chapter of Kasoku Kids appeared
   and customer relations are now being written in            on December 26, 2008. Kasoku means “acceler-
   Manga style.                                               ation” in Japanese, and when combined with the
       Takuya Uruno, whose work appears on the                first two characters of “kids” in English it becomes
   cover of this issue and on page 30, specializes            kasokuki, meaning “accelerator.” We have been
   in drawing Manga for companies to use in public            publishing chapters at the end of each month
   relations and for educating recruits. When he first        since then, and will continue until the final
   turned up at the KEK campus, he wore samue—                chapter, expected late next year.
   down-to-earth, casual, Japanese-style work                     The story line involves four kids trying to find
   clothes—and a pair of zohri, sandals made from             a theme for their summer project. In the pro-
   hand-woven grass stalks, which were quite                  cess, they meet the imaginary Dr. Fujimoto and
   an unusual sight even at KEK. We discussed the             Dr. Takahashi and start to learn about various
   possibility of collaborating on a physics edutain-         aspects of nature and ongoing research at KEK.
   ment series, and he instantly jumped on the idea.              The series has gained some popularity among
   Though he did not know much about research                 science-fan bloggers. However, the best is yet
   at KEK, he was enthusiastic about conveying the            to come. We are planning a print publication to get
   marvels of the research to the younger generation.         more exposure at our annual open house and
                                                                                                                                                               symmetry | volume 06 | issue 04 | august 09




   We talked for hours about classical and                    to circulate materials to other academic activities
   legendary Manga works, comedies, and jokes.                and so on.
       Then I asked him a rather rude question: “Do               Kids these days seem to be absorbed in
   you wear those clothes even when you meet                  instant-communication devices, such as mobile
   company executives?” His answer was amusing.               phones and the Internet. One of these days,
   He purposefully wears them because people in               I may have to shout at my kids, “Manga
   Japan, especially the older generation, still have         demo yonde benkyo shinasai!”—study hard by
   a certain kind of stereotyped impression of Manga          reading Manga!
   artists. “It helps my business if my fashion
   meets their expectations,” Uruno said, smiling.            Youhei Morita is head of communication at KEK, the High
                                                              Energy Accelerator Research Organization, in Tsukuba, Japan.
       Despite the recent popularity of Japanese
   Manga culture, he says making a living from
   Manga is tough: “There is still the old master-
   and-assistant system in this guild. There are so
   many young Manga artist wannabes out there,
   but only one in thousands might get enough earn-
   ings from the magazine publishers.” He felt he
   needed to modernize the system for Manga artists,
   and started his own company that handles
                                                          3
signal to background

Learn physics from evil slugs; South Pole researchers with the right stuff; the
butterfly hunter; no dirty SNO in Canada; if you can’t make it, send your avatar;
letters; correction.
 Image courtesy of CERN




                          Welcome to                             CERNland is loaded with          French, or Italian, the site was
                          CERNland                           games and activities, but also       launched as part of CERN’s
                                                                                                                                       symmetry | volume 06 | issue 04 | august 09




                          Alberto sits down at a computer    requires children to learn           celebration of the 20th anniver-
                          and brings up a clickable map      a handful of facts about CERN        sary of the World Wide Web.
                          of CERN. But rather than dry       and its Large Hadron Collider.       Robert Cailliau, a CERN systems
                          text, he is greeted with bright,   They must answer questions to        engineer who was involved in
                          musical animation, a pinball       move forward in a Super Mario        the development of the Web,
                          game, a quiz show, rocket ships,   Bros.-style game or to win           helped launch the site, and said
                          evil slugs, and music videos.      a game show and earn the title       he’s glad to see CERN using
                              Soon the 11-year-old and his   of “Antimatter Researcher.”          the Web to reach out to kids.
                          classmates are glued to the           “We target an age range of            The Web site’s initial success
                          monitors and navigating their      7 to 13. That’s when kids discover   already has producers planning
                          way through CERNland, an           science,” says Silvano de            new games about the history of
                          interactive Web site designed      Gennaro, project leader for          the universe and the links
                          to help kids learn about the       CERNland. “Also, at that age their   between science, technology,
                          European lab, its experiments,     imaginations are so completely       and everyday life.
                          and particle physics.              unrestrained that they can easily        Try the game at: https://
                              The students, from the         grasp some pretty awkward            project-cernland.web.cern.ch/
                          International School of Geneva,    concepts, such as those you find     project-cernland/.
                          tested the Web site before its     in particle physics.”                Calla Cofield
                          spring public debut.                   Available in English, Spanish,
                                                                             4
                                                                  to predict the behavioral effects        time in the museum’s breeding
                                                                  of long space missions. QUaD’s           lab, that pregnant purplish cop-
                                                                  winter-over, a support scientist         per butterfly produced hun-
                                                                  and amateur paraglider named             dreds of eggs, which became
                                                                  Robert Schwartz, passed up               ammunition in the battle to
                                                                  a seventh year of Antarctic win-         repopulate the species in
                                                                  tering in 2008 to enter the              northern Illinois and eventually
                                                                  race to be an ESA astronaut.             the entire state.
                                                                  Although he wasn’t selected,                 The purplish copper, distin-
                                                                  he was one of only 192 out               guished by a purple tint on




                                                                                                                                                                                 symmetry | volume 06 | issue 04 | august 09
                                                                  of the 10,000 candidates who             the male’s wings that fades with
                                                                  passed the initial medical               age, has lost habitat to farm-
                                                                  exam, to make it to the fourth           ing and subdivisions in Illinois
                                                                  round of physical and psycho-            and other parts of the Midwest,
                                                                  logical screening.                       as well as in the eastern
Photo courtesy of Ed Wu




                                                                      But according to Wu, good            United States.
                          South Pole physics                      health is not enough to keep                “Fermilab is one of two areas
                          is not for wimps                        people sane despite oxygen               that retain big populations, and
                          Ed Wu has never been to space,          deprivation, cabin fever, and            all of our breeding stock comes
                          but he probably has a better            extreme cold.                            from Fermilab,” says Doug
                          idea of what it’s like than the            “People skills really do matter,”     Taron, curator of biology at the
                          rest of us.                             he says. “You have to be com-            museum, which is working to
                               Working at the South Pole          fortable working with people             restore populations of butterfly
                          on the now-retired QUaD                 regardless of how you feel               species that were common at
                          instrument, the experimental            personally, because nothing gets         the turn of the century.
                          cosmology graduate student              done at Pole without everyone.               More than 50 butterfly spe-
                          from Stanford University lived in       You also have to be able to              cies find a haven on the lab’s
                          close quarters with a small             derive pleasure from what you            6800-acre campus, which
                          group of people, surrounded by          can.” For Pole dwellers, that            includes 1100 acres of restored
                          extreme weather, and all but            can mean anything from making            native prairie and hundreds
                          cut off from home.                      a short film for the South Pole          of acres of farm fields, wood-
                               The dry, rarified air suited the   International Film Festival              lands, and wetlands.
                          instruments Wu used to study            to taking a very hot sauna and               It’s difficult to say, for any
                          high-resolution readings of the         running naked to the South               species, what will happen if it
                          cosmic microwave back-                  Pole marker and back. “It’s as           vanishes, Taron says: “But the
                          ground—microwaves emitted just          normal as you make it,” Wu says.         less biodiversity you have, the
                          300,000 years after the big bang,       Lauren Schenkman                         worse it is for the ecosystem.”
                          more than 13 billion years ago.                                                  Butterflies’ pollination of plants
                               Before he could go to “Pole,”      He stalks rare prey                      and critical place in the food
                          as the locals call it, he had           for its own good                         chain make them valuable for
                          to undergo a thorough medical           Tom Peterson loves hunting               much more than aesthetic
                          and dental exam—think less              season.                                  reasons.
                          a yearly physical, and more the             He spends his lunch hours                The females Peterson bags
                          initial screening the European          scouting the best spots, and             in this year’s hunt will be
                                                                                                                                                Photo courtesy of Tom Peterson




                          Space Agency gives prospec-             weekends lurking around the              put on display in the museum’s
                          tive astronauts.                        edges of Fermilab’s ponds                breeding lab and their descen-
                               Twenty-four-hour sunshine          and moving as silently as he can         dents moved to new homes in
                          and the exhausting scarcity             through old fields. He doesn’t           forest preserves, where
                          of oxygen at 10,000 feet make           want to scare his pregnant               museum staff hope they will
                          life at Pole surreal. The summer        quarry. The season is short, the         settle in and lay their eggs.
                          population hovers around 200,           targets small and elusive.               Tona Kunz
                          and satellites provide contact              Ask the Fermilab engineer,
                          with the outside world only             who specializes in cryogenics,
                          seven or eight hours a day. After       why he endures the heat and
                          the sun goes down in May,               the dirt and he’ll tell you it’s for a
                          Pole’s 50 “winter-overs” won’t          good cause: saving ecosystems.
                          see it again until August. In the           When he bagged a beauty
                          meantime, there are no visitors,        last year, he gave it to a friend
                          cargo drop-offs, or rides home.         at the Chicago Academy
                               Psychologists have studied         of Sciences’ Peggy Notebaert
                          the experiences of winter-overs         Nature Museum. After spending
                                                                                    5
signal to background

                                   A scrub+ for SNO+                     a scintillating liquid called LAB,    fractures, or holes. He’ll do
                                   Imagine a house-sized acrylic         or linear alkyl benzene. This         the same thing for the accessi-
                                   fishbowl inside a giant, shiny,       will allow detection of neutrinos     ble photomultiplier tubes.
                                   disco-ball-like sphere, sus-          with much lower energies that             When he flicks on his
                                   pended in a cavern as tall as a       come from the sun, exploding          flashlight, reflectors in the pho-
                                   10-story building. Now imagine        stars, or natural radioactive         tomultiplier tubes beam light
                                   climbing around inside that           decays in the earth.                  in all directions.
                                   pitch-dark fishbowl with                  To take full advantage of this,      “There is so much light being
                                   a squeegee and a flashlight.          Skensved says, the detector           reflected back at you that
                                       Peter Skensved does that          has to be as free of contami-         some people get a little seasick,”
                                   once or twice a week.                 nants as possible. For SNO,           he says.
                                       For the past few months, the     “clean” meant keeping levels of            Scientists use high-pressure,
                                   Queen’s University physicist          uranium and thorium contami-          ultra-pure-water sprayers
                                   has tackled dirt, cracks in glue      nants in the water a factor of        and squeegees on really long
                                   joints, rips in liners, and dead      a billion lower than those found      poles to scour parts of the
                                   photomultiplier tubes as he helps     in dirt and one million times         interior walls.
                                   to convert the SNO particle           lower than on the acrylic ves-            The detector must be
                                   detector in Ontario, Canada, for      sel’s surface. Essentially, the       scrubbed inside and out, but its
                                   a new project called SNO+, pro-       allowable contaminant amount          curved, ultra-smooth walls thwart
                                   nounced “snow-plus.”                  could equal the size of one           climbing. So Skensved is work-
                                       SNO stands for Sudbury            gram of dust embedded on              ing out a plan to reach difficult
                                   Neutrino Observatory, an experi-      the vessel.                           spots: scaffolding, a seat low-
                                   ment in a working mine two                For eight-to-10-hour              ered by rope, or floating docks.
                                   kilometers below ground. Its          stretches, he sits in a rubber            When the detector is almost
                                   transparent, spherical detector       boat floating in the old water and    ready to operate, Skensved
                                   was filled with heavy water           peers at, patches, and scrubs         will hand-sand radon residue off
                                   that gave off Cherenkov light         the cavity’s plastic liner and the    the walls, likely underwater
                                   when a neutrino passed                detector’s acrylic panels. He         to prevent too much radon from
Photo courtesy of Peter Skensved




                                   through. Photomultiplier tubes        rides the water down as it            getting in the air.
                                   picked up these light signals         slowly drains, exposing new               After the contaminated
                                   and passed them on to com-            sections for inspection. He           water drains away, the detector
                                   puters for analysis.                  removes an oil film left from a       will be ready for the pure
                                       For its successor, SNO+,          water pump seal break and             new liquid and physics results
                                   scientists are draining the           searches for signs of material        to come.
                                   detector. They will refill it with    stress, such as bubbles, hairline     Tona Kunz
                                                                                                                                                    symmetry | volume 06 | issue 04 | august 09




                                                                                         6
                                                                           The talk was broadcast          nearly three decades ago. He
                                                                      live over projection screens on      still does that, but you can also
                                                                      Astronomy 2009 Island in             catch his talks on YouTube,
                                                                      Second Life, the online world        read about them in 140-word
                                                                      that simulates buildings, places,    Tweets, find Facebook pages
                                                                      and people interacting as they       related to the scientists and
                                                                      would in real life. Dechow’s vir-    experiments he talks about, and
                                                                      tual self, or avatar, was in         follow links to his talks from
                                                                      the island’s virtual audience as     various blogs.
                                                                      White explained the search                And now the physicist from




                                                                                                                                               symmetry | volume 06 | issue 04 | august 09
                                                                      for the Higgs boson, the use         Illinois has been instantaneously
                                                                      of antimatter in medical diag-       brought face to face—sort of—
 Photo courtesy of Doug Dechow




                                                                      nostic tools, and how particle       with Dechow, a librarian from
                                 Physics talk 2.0                     accelerators are used to study       Chapman University in California.
                                 From his California office, Doug     the basic components of matter.      Tia Jones
                                 Dechow stretched out on a                 Avatars from across the
                                 grassy hill and listened to a par-   nation e-mailed questions to
                                 ticle physics lecture taking         White and shared instant-mes-
                                 place in Chicago.                    saged comments as easily as
                                     He hadn’t found an often-        if they were sitting side by side.
                                 theorized parallel universe, but         “Since we started using
                                 a real virtual one.                  Astronomy 2009 Island, the
                                     In celebration of the            reach of our lecture attendance
                                 International Year of Astronomy,     has increased 25 percent,”
                                 Adler Planetarium had added          says Nancy Ross Dribin, direc-
                                 an extra seating option for          tor of interactive media at Adler.
                                 a lecture by Fermilab physicist           White started giving talks
                                 Herman White.                        to flesh-and-blood audiences



letters
                                 60 seconds of science teaching
                                 Thanks tons for the archive of “Explain it in 60 Seconds” articles. These are
                                 great! As a high school physics teacher working here at Fermilab for the
                                 summer, I’m finding these are a great resource for me and will end up finding
                                 their way into my classroom. I immediately sent that link to the other
                                 teachers working at Fermilab that I have access to, about 10 of us in two
                                 different programs.
                                 Terry Barchfield
                                 Editors’ note: Past “60 seconds” articles are archived at www.symmetrymagazine.org/60seconds/

                                 Remembering “a frog’s place”
                                 Reading your May 2009 commentary, “Bosons and Grocery Bags,” it struck me that I had to write.
                                     We remember the Fermilab site as “A Frog’s Place,” wooded with an old barn and lots of kids,
                                 where we dropped our son Ken off for a camping experience in a summer of the ’60s. It was the end
                                 of an idyll, replaced the following year with a long, unbelievably deep trench through which Fermilab’s
                                 accelerator soon would burrow. It was a dream then, one that perhaps our son could begin to imagine.
                                 He was, and still is, a sci-fi nut, now with maturing offspring of his own.
                                     I’ll never forget that ditch (nay, more a canyon), partly because my wife and I have been drawn to
                                 Fermilab at least once a year since the ’60s. I can follow only parts of symmetry. I scan each issue,
                                 then return to a few of the articles that make the most sense. In fact, I’m postponing reading the
                                 60-second article, “Charm Quark,” on the back cover. Dessert, you know.
                                     Miracle? I don’t know. Awe? Definitely.
                                 Dick Jacoby, Willowbrook, Illinois

                                 Correction
                                 A feature in the July 2009 issue of symmetry on the world’s dwindling helium supply did not properly
                                 introduce the physicist who manages the Cryogenic Dark Matter Search at Soudan Mine in
                                 Minnesota. He is Dan Bauer.
                                                                                      7
symmetrybreaking
   Highlights from our blog
   Fermi telescope cap-                 Dark matter may                     Another cosmic-
   tures a solar eclipse                be brighter than                    ray puzzle: Are
   July 24, 2009                        expected                            iron nuclei
                                        July 17, 2009                       bombarding Earth?
                                                                            July 13, 2009




                                        The Fermi Gamma-ray Space
                                        Telescope may find dark matter
   The Fermi Gamma-ray Space            in our galaxy more easily than
   Telescope was launched to study      expected. Theoreticians have
   gamma rays, not sunshine.            demonstrated that small clumps      For decades, scientists have
   Yet that’s what it has done, most    of dark matter in our galaxy        thought that the highest-energy
   recently last week, when one         and others like it may be more      cosmic rays—those packing up
   of its instruments registered sig-   visible than previously thought.    to a million trillion electronvolts—
   nals from a solar eclipse.                                               were almost exclusively protons.
                        Feynman                                             But data from the Pierre Auger
   A helium atom walks “Messenger” lectures                                 Observatory in Argentina may
   into a bar…          now available online                                tell a startlingly different story.
   July 21, 2009                        July 15, 2009
                                                                            Wood from NOνA
                                                                            site fuels renewable
                                                                            energy in Minnesota
                                                                            July 10, 2009
                                                                            Rather than wasting wood
                                                                            cleared from the detector con-
                                                                            struction site, a logging company
                                                                            will sell it to two Minnesota
   Brian Malow is living proof that
                                                                            power plants.
   a science comedian can actually
   invoke laughs from his audi-
   ence instead of groans. While
                                                                            BaBar’s hunt for an
   researching a feature for the
                                                                            exotic Higgs particle
                                        A set of seven talks by legend-
                                                                            July 7, 2009
   current issue of symmetry on the     ary, Nobel-winning physicist
   limited supply of helium on Earth    Richard Feynman is now avail-
                                                                                                                   symmetry | volume 06 | issue 04 | august 09




   and how a helium shortage            able online, free of charge and
   would affect high-energy phys-       through a much more versatile
   ics, I came across a five-minute     application than YouTube.
   talk Malow gave on the subject.
                                        Physicists on a plane
   LHC update                           July 14, 2009
   July 20, 2009
                                        To some people, physicists are
   In the latest issue of the CERN      even scarier than snakes on
   Bulletin, the laboratory reports     a plane. A piece in yesterday’s
   that vacuum leaks have been          New York Times with Michael
   found in two “cold” sectors          Tuts, experimental particle phys-   The BaBar collaboration submit-
   of the Large Hadron Collider.        icist at Columbia University        ted two papers to Physical
   Repairing the leaks will require     and frequent traveler to CERN,      Review Letters last month, both
   the affected part of each sector     discusses how his seatmates         searching for hypothetical
   to be warmed to room temper-         react to him being a physicist.     light-mass Higgs bosons, the
   ature, but will not affect the                                           particles suspected of giving
   vacuum in the beam pipe. The                                             objects their mass. Neither found
   repairs will push the collider’s                                         evidence of a low-mass Higgs
   restart date to mid-November.                                            in the BaBar data set.
                                                        8
Read the full text of these stories and more
at www.symmetrymagazine.org/breaking

“Beyond our wildest                     Fermilab’s CDF                       Dancing with science,
 dreams:” Fermi scope                   observes Omega-                      or, a little light music
 bags 16 gamma-ray-                     sub-b baryon                         June 25, 2009
 only pulsars                           June 29, 2009
July 6, 2009




After only one year of operation,
the Fermi Gamma-ray Space
Telescope has already outper-                                                Before the official speeches
formed researchers’ best                                                     began at the National
                                        The discovery of this “doubly        Synchrotron Light Source II
expectations. In two papers,
                                        strange” particle, predicted by      start-of-construction celebration,
researchers reported a new
                                        the Standard Model, is signif-       a lone dancer in fluorescent
class of pulsar and evidence that
                                        icant because it strengthens         green commanded the attention
helps explain how gamma-ray
                                        physicists’ confidence in their      of the audience with tribal
emission occurs.
                                        understanding of how quarks          stomps and dramatic leaps, per-
                                        form matter–and because              forming a contemporary
World Science                           it conflicts with a 2008 result
Festival: Time since                                                         dance piece titled “Time and
                                        announced by CDF’s sister            Space for Celebration.”
Einstein                                experiment, DZero.
July 1, 2009
                                                                             New ways to power
                                        A Higgs boson with-                  particle accelerators
                                        out the mess                         June 16, 2009
                                        June 26, 2009




“Time, I think, is a little bit like
 love,” began moderator John
 Hockenberry. “It’s accessible to
 all of us; it is intuitively experi-
                                        Physicists at CERN’s Large
 enced by all of us in the same
                                                                                                                     symmetry | volume 06 | issue 04 | august 09




                                        Hadron Collider hope to discover
 way; yet it retains its mystery at
                                        the Higgs boson amid the
 whatever level you weigh in on it.”
                                        froth of particles born from pro-
                                        ton-proton collisions. Results
Researchers find                        from an experiment at Fermilab
                                                                             Yesterday, a team of SLAC
evidence for the                        show there may be a way to
                                                                             physicists and engineers put the
origin of cosmic rays                   cut through some of that froth.
                                                                             final touches on a revolutionary
June 30, 2009                                                                new power source, the Marx
                                                                             modulator, and threw the switch.
                                        Steven Chu’s energy                  This milestone launches the
                                        challenge                            final step in proving the reliability
                                        June 26, 2009
                                                                             of a device poised to transform
                                        Speaking at SLAC, Secretary of       the way particle accelerators
                                        Energy Steven Chu said, “For the     are powered.
                                        first time in history, science has
An international team of                shown humans altering the des-
researchers has discovered              tiny of our planet in a meaningful
strong evidence that extremely          way. We have to try to enlist
energetic cosmic rays are               some of the very best intellectual
born in supernova remnants.             horsepower to deal with this.”
                                                        9
Illustration: Sandbox Studio




                                     Fermilab is cooking
                                     up a hot technology—
                                    and the serving is
                                   ultracold. The lab oratory
                                  is stepping up efforts to
                                  develop and test superconducting
                                 radio-frequency cavities, a key
                                technology for the next generation
                               of particle accelerators and the futu
                                                                     re
                               of particle physics. By Kathryn Gr
                                                                  im
                                             10
11
     symmetry | volume 06 | issue 04 | august 09
                             Fermi National Accelerator Laboratory has been known
for innovations in the design and construction of particle accelerators.
    Its scientists and engineers developed the materials needed to build the super-
conducting magnets that steer protons and antiprotons in Fermilab’s particle
collider, the Tevatron. The same technology now beats in the heart of the Large
Hadron Collider at the European laboratory CERN.
    Now the Chicago-area lab is learning the ropes of a new accelerator
technology considered crucial to the future of particle physics: superconducting
radio-frequency cavities.
    SRF technology is a highly efficient way to accelerate beams of particles.
It starts with shiny, curvy, virtually perfect cells made of niobium, a super-
conducting metal, and strung together like hollow pearls. Several strings, or
cavities, nestle in a vessel called a cryomodule, which bathes them in liquid
helium and keeps them at the ultracold temperature that is key to their operation
and efficiency.
    Fermilab is not the first laboratory to use SRF. In the United States, Thomas
Jefferson National Accelerator Facility and Cornell University have greatly
advanced the technology. The German laboratory Deutsches Elektronen-
Synchrotron, or DESY, has been developing SRF technology for more than a decade
and uses it in its new X-ray laser. Other European and Asian laboratories have
also gained expertise in this area and have begun the process of industrializing
the production of SRF cryomodules.
    Now, with more than $55 million from the American Recovery and Reinvestment
Act—better known as the economic stimulus package—Fermilab is poised
to expand its SRF test facility and take its place among these leaders, while at
the same time helping boost American manufacturing capabilities.
    With help from DESY and Italy’s Istituto Nazionale di Fisica Nucleare (INFN),
Fermilab engineers have already assembled one SRF cryomodule and are working
on a second one. Working with several companies and with the help of other
national labs, they are preparing to build a fully functioning prototype SRF accelerator.
   “We struggled for the last year and a half due to budget problems,” says Jerry
Leibfritz, project leader of Fermilab’s SRF test facility. “Now everything’s ramping
back up. The stimulus money is going to get us back on track and give us the R&D
infrastructure to become a leader in SRF technology.”

A step toward Project X
Fermilab scientists hope that work at the test facility will culminate in the
construction of new particle accelerators in the United States. One has a curious
name: Project X, a new proton accelerator proposed for the Fermilab site, where
it would fit nicely in the center of the four-mile Tevatron collider ring.
    Project X would replace an aging linear accelerator and booster ring, which
generate protons for the Fermilab collider and neutrino programs, with a new
accelerator complex that could provide three times as many protons in beams with
up to two megawatts of power, a world record. Physicists would use the new
proton source to create the most intense beams of subatomic particles—including
neutrinos, kaons, and muons—ever made in the laboratory. What’s more, the
new machine would generate beams for several experiments at once, each at the
right energy and with the right type of particle.
    Physicists could also use Project X as the front end of a new kind of energy-
frontier collider, one that makes beams of muons collide.
   “We want to run multiple projects simultaneously,” says Fermilab’s Ron Ray, project
manager for an experiment called Mu2e. “Project X can give us that kind
of flexibility.”
    Building Project X would provide Fermilab with a new, top-notch particle
physics research program following the planned closing of the Tevatron, which will
soon be eclipsed as the most powerful collider in the world by the Large Hadron
Collider in Europe. It will also provide several options for future upgrades to the
Fermilab accelerator complex.
    Once approved, Project X could be built over a five-year period starting in
2013 or 2014; “It all depends on funding,” says Steve Holmes, Fermilab associate
director for accelerators.
                            12
   Scientists at Fermilab are considering various configurations for this upgrade,
but “it’s almost irrelevant what the exact design will be,” says Sergei Nagaitsev,
project manager of the lab’s SRF test facility. “SRF is going to be the bread and
butter for future accelerators.”

A necklace with kick
An SRF cavity resembles a pearl necklace pulled into a straight line. Running
through the string of pearls, or cells, is an electric field that oscillates between
positive and negative at a rate of 1.3 billion cycles per second. Each cycle, or
wave, swells to its peak and sinks to its valley within the space of a single cell;




                                                                                           symmetry | volume 06 | issue 04 | august 09
it is as if each cell rapidly switches between a positive and negative charge.
     The cycles are timed to kick charged particles riding the wave from cell to cell.
Each time a positively charged proton enters a cell, that cell’s charge changes to
negative, which attracts the proton. As the proton leaves the cell, the cell’s charge
changes to positive and pushes the proton forward. Traversing the next cell, the
proton is propelled in the same fashion. This process continues until the particle
has shot all the way through the accelerator.
     The design of the prototype accelerator at Fermilab’s SRF test facility is similar
to the one proposed for the International Linear Collider, a proposed electron-
positron collider. Each cavity will be a necklace of nine cells, and eight of these
cavities will fit into a cryomodule. When complete, Fermilab’s prototype accelerator
will have six cryomodules.
     Superconducting radio-frequency cavities are difficult to make because they must
be almost flawless. Their production and assembly must take place in clean rooms.
The slightest irregularity or even a speck of dust would throw a cavity off kilter.
    “The complexity is exaggerated by the fact that after you assemble everything,
cool it, and put it into operation, you can no longer access the individual components,”
Nagaitsev says. “It’s as if you assemble the cryomodule and then send it into space.”
     It now takes several months to produce a single ILC-type cryomodule; at that
rate, even with Europe, Asia, and North America working together, it would take
hundreds of years to craft the 1600 cryomodules needed for the ILC.




The name of a proposed project to upgrade Fermilab’s accelerator complex
sounds like something out of science fiction.
    A steering committee found it difficult to name a project with the potential
to transform the abilities of the Fermilab accelerator complex in various
ways, so they started using “Project X” as a placeholder until they came up
with something else.
   “We weren’t worried about the name,” says Fermilab Deputy Director
Young-Kee Kim, who chaired the committee. “We were worried about the
content of our discussion.”
    The name sometimes leads to confusion.
    Fermilab physicist Sergei Nagaitsev recently included the name “Project X”
in the title of a presentation he was to give at a conference in Russia. “I waited
and waited, and they didn’t get back to me,” he says. When he finally contacted the
organizers of the conference, they told him that they thought his registration was
incomplete. “You’ve left an X in your title,” they said.
    Kim is still accepting suggestions for a new name. But by now, it may be too
late to change it.
   “At this point it’s a pretty recognized name in the community,” says Steve Holmes,
Fermilab associate director for accelerators. “Personally, I like it.”
   “Project X” found firmer footing when the media fell in love with the moniker,
which is also the title of a 1987 film about a military animal-testing conspiracy star-
ring young actors Matthew Broderick and Helen Hunt, along with a chimpanzee.
   “The name took on a life of its own and stuck,” says Ron Ray, project manager
for Fermilab's Mu2e experiment.



                                                        13
                       Saving energy with SRF
                       Cooling the SRF cavities to ultra-low temperatures in cryomodules has a huge
                       benefit: It saves energy. When chilled to almost absolute zero, SRF cavities have
                       no electrical resistance and conduct electrical currents without loss.
                          Working with several companies and Department of Energy national laboratories,
                       Fermilab is trying to find ways to make the production of cavities and cryo-
                       modules faster and cheaper, so the process can be industrialized. Although the
                       laboratory has never used SRF technology in its accelerators, Fermilab
                       engineers do have lots of experience working with the Tevatron’s superconducting
                       magnets, which also operate at cryogenic temperatures.
                          The cryomodules for Project X would not necessarily be built to the same
                       design as the ones for the ILC. Even so, building them brings Fermilab and American
                       companies closer to having the capability needed to build future accelerators,
                       says Fermilab scientist Bob Tschirhart.
                         “You can learn a lot about how to build a Ford by building a Chevy,” he says. “The
                       designs share a lot of the same components.”

                       Neutrinos and more
                       The first use for Project X would be to produce the world’s highest-intensity neutrino
                       beam, a project that lab Director Pier Oddone would like to start as soon as possible.
                          “Ideally, we don’t let grass grow under our feet,” Oddone says. “Right
                       now if we make a move, we have the opportunity to attract many collaborators.”
                           Neutrinos are some of the most abundant and least understood particles in
                       the universe. They very rarely interact with matter, so they can pass through the
                       entire Earth as if it were empty space. Yet scientists think that neutrinos played
                       a critical role in the early universe.



 1   Main Injector
 2   Neutrino Beam to Northern Minnesota
 3   Neutrino Beam for Booster Neutrino Experiments
 4   Antiproton Source
 5   Linear Accelerator and Cancer Treatment Center
 6   Booster Ring
 7   Wilson Hall
 8   Proposed Location for Project X
 9   Beam for Detector Test Facility
                                                                                                                9
10   SRF Test Facility
11   Tevatron Collider
                                                                                            7
                                                       2                        5
                                                             3
                                                                           4         6
                                                                                                          8
                      1




                                                  14
   “It’s our role to understand the basics of matter’s interactions, and neutrinos are
one area where we don’t have that understanding yet,” says Fermilab physicist
Bob Zwaska. “Neutrinos are a basic unit of the universe. They’re everywhere. And
they fit into larger puzzles too—cosmology, matter-antimatter asymmetry and the
dynamics of supernovae.”
    Fermilab has conducted neutrino experiments since the 1970s. In 2005,
the laboratory launched the MINOS experiment, which studies a beam of neutrinos
that travels from Fermilab to a detector in an underground mine 450 miles
away in Minnesota. Two months ago, Fermilab broke ground for another long-
distance neutrino experiment: NOνA. More neutrino experiments are in the




                                                                                                                            symmetry | volume 06 | issue 04 | august 09
planning stages.
    NOνA and future neutrino experiments would benefit from better, higher-intensity
neutrino beams. Project X could provide those beams.

Meet the muons
But neutrinos are not the only particles that may hold the key to expanding our
understanding of the world around us. Scientists are also interested in their
electrically charged cousins, including the muon. The study of muons could give
scientists insights into physics beyond the Standard Model. Theoretical models
such as supersymmetry predict quantum effects in muons and other leptons that
could be cleanly detected and unambiguously interpreted as new physics.
   The proposed first phase of Fermilab’s charged-lepton research program, the
Mu2e experiment, would take place before breaking ground for Project X. But if
Fermilab goes on to build Project X, physicists could upgrade the Mu2e experiment
and measure muon interactions and decays more thoroughly, with a much more
powerful beam.




                                          NORTH

   10




                    11




                                                                                         Located 45 miles west of Chicago,
                                                                                         Fermilab’s particle accelerator
                                                                                         complex provides beam to particle
                                                                                         physics experiments, test facilities
                                                                                         and a cancer treatment center.
                                                                                         The proposed Project X would
                                                                                         replace the 40-year-old linear
                                                                                         accelerator and booster ring with
                                                                                         a high-intensity proton accelerator.
                                                                                         Photo: Reidar Hahn, Fermilab



                                                       15
Fermilab has begun to install the first components of a proto-
type accelerator in its SRF test facility. Scientists expect that
superconducting radio-frequency cavities will be the technology
of choice for the next generation of particle accelerators.
Photo: Reidar Hahn, Fermilab




                                                                    16
  “Project X would allow us to extend the investment we made in Mu2e,” Ray says.
   Farther into the future, the SRF technology could lead to the International
Linear Collider. Scientists in Europe, Asia, and North America already are working
on the design of such a machine.
   And decades from now, Project X could also feed into a new kind of high-
energy collider, one that brings beams of muons into collision. Muon collisions are
easier to study than collisions between protons, the particles that will speed
around the Large Hadron Collider; and a muon collider could reach much higher
energies than an electron-positron collider.
  “Superconducting radio-frequency technology will be a big part of high-energy




                                                                                                                           symmetry | volume 06 | issue 04 | august 09
physics in the future,” Ray says. “Work at our test facility will give us the real
experience of building an accelerator of that type.”

Expanding the test facility
Fermilab will use Recovery Act funds to double the length of its existing SRF
test facility, which is now about 70 meters long. This will extend the building enough
to encompass a complete prototype accelerator with additional test beam lines.
    Recovery Act funding will also go toward building the cryogenic plant that
Fermilab needs to cool SRF cryomodules to minus 271 degrees Celsius, the oper-
ating temperature for SRF technology. The plant will have the capacity to cool
future cryogenic projects as well, turning the Fermilab complex into one of the
best SRF R&D centers in the world.
    Engineers from DESY and INFN supplied the parts and assistance necessary
to assemble the first SRF cryomodule at Fermilab. Fermilab plans to finish
a second cryomodule, this one with some American-made parts, in early 2010.
The assembly of these cryomodules represents the crucial step of going from
a set of blueprints to building an accelerator.
    European manufacturers of SRF technology have an advantage over manu-
facturers in the United States: They have been working on this technology for
more than 20 years. Whereas about 80 percent of the cavities they build meet
the standards Project X would require, only about 50 percent of American-made
cavities now make the cut.
    Over the next few years, engineers at Fermilab plan to catch up with their
European counterparts and further spur manufacturing capabilities in the United
States. So far, three American companies are building SRF cavities.
    Whether or not Project X comes to fruition, Fermilab will benefit greatly from
its new SRF test facility, Oddone says: “Our SRF test facility opens broad
horizons. It will move us forward with our Project X plans, and prepare us to build
the next-generation particle collider.”




                                    SRF Test Facility


                                                                                         Fermilab plans to double the length
                                                                                         of its existing SRF test facility
                                                                                         to make room for a longer proto-
                                                                                         type accelerator with additional
                                                                                         test beam lines. Image courtesy
                                                                                         of Fermilab.




                                                       17
Photo: C. Marcelloni, ATLAS experiment, CERN




Not a moment
to lose
at the LHC                                     18
Physicists from the Large Hadron Collider’s
experiments turn an unexpected shutdown
to their advantage.

By Kate McAlpine




                                                                          symmetry | volume 06 | issue 04 | august 09
The eyes of the world were on the Large Hadron Collider at CERN on
September 10, 2008. On that day, dubbed “Big Bang Day” by the
BBC, the first beams of subatomic particles zoomed around the
17-mile-long, super-cooled particle accelerator. Three hundred feet
below the Swiss-French border near Geneva, the LHC had been
more than 20 years in the making. It was designed to bring particles
into collision at energies high enough to recreate conditions last
seen a fraction of a second after the big bang.
    Everything went smoothly on Big Bang Day. But less than two
weeks later, a connection between two superconducting magnets
failed, setting off a chain reaction that would damage 53 of the accel-
erator’s 1624 main magnets and require a full year to fix.
    Physicists at the LHC’s four major experiments had been eagerly
anticipating the first collisions, which would have taken place about
a month after the first beams. While those initial collisions would
have been too low in energy to reveal new truths about the universe,
they would have provided vital information about the inner workings
of the LHC’s brand-new, incredibly complex, one-of-a-kind detectors.
    But even with the accelerator shut down, there has been no
time to relax. Physicists not involved in major repairs to the collider
have been busy upgrading both equipment and software, making
minor fixes that originally had been scheduled for the LHC’s first
winter shutdown, and repairing nagging problems that cropped
up during years of construction.
    Most of this work is routine, part of the ordinary process
of commissioning a new accelerator, says James Gillies, head of
communication for CERN.
   “It’s part of the normal process,” he says. “When you really are
pushing the limits of technology, things like this can happen. That’s
one of the ways technology advances.”
    Here’s a look at a few of those projects.
                                  19
ALICE: Doors that make a sloth look quick                    the cavern. This gigantic red shell curves the
Physicists are always looking for ways to improve            paths of charged particles such as electrons,
and enhance their experiments, whether through               allowing physicists to measure their speeds and
small changes to software or the addition of whole           masses. Opening the magnet’s doors takes
new sets of detectors. The year-long shutdown                a full day. Each door is 90 feet tall and 30 inches
gave the scientists of ALICE, one of the LHC’s               thick, and weighs 430 tons. As the hydraulically
four large experiments, a head start on installing           driven doors swing out to a 90-degree angle, they
their newest subdetector system.                             move slower, on average, than the hour hand
    Subdetectors measure the trajectories,                   of a watch.
energies, and arrival times of particles that pass               With the doors open, the first electromag-
through the detector. Each subdetector is tuned              netic calorimeter module was lowered 150 feet
to specific types of particles. It’s up to the physi-        into the cavern, already locked into the yellow
cists to build a coherent picture of what hap-               frame of its installation tool. Then the tool’s
pened in a given collision by stitching together             internal motors rotated the module into the
millions of pieces of such information.                      proper alignment.
    ALICE’s newest subdetector system, a joint                  “You slide it in on rails, and then you simply lock
contribution of the 13-institution ALICE-USA col-            it on the rails such that it cannot move any-
laboration and CERN, is made up of 11 eight-ton              more,” explains Werner Riegler, ALICE’s deputy
electromagnetic calorimeters that absorb and                 technical coordinator. Once it was in place, the
measure the energies of electrons and photons,               calorimeter teams brought the module to life,
or particles of light.                                       connecting it with cooling, electricity, and data-
    The first step in the installation was to open           carrying fibers. Four of the modules will be
the massive doors of the L3 magnet, which had                installed by the time beams are back in the LHC;
been recycled from a previous experiment in                  the rest should be in place by 2011.




ALICE Photo: C. Marcelloni, ATLAS experiment, CERN



                                                        20
                         LHCb: Those hard-to-reach places
                         Throughout the six years of the LHCb experiment’s
                         construction, workers were continually building,
                         tearing down, repositioning, and rebuilding the
                         ladders and scaffoldings that allowed physicists,
                         engineers, and technicians to get to hard-to-reach
                         places. The arrival of the first LHC beams
                         signaled the end of construction; now the way was
                         clear for the installation teams to build the
                         permanent staircases, handrails, and platforms




                                                                                symmetry | volume 06 | issue 04 | august 09
                         needed to safely reach and maintain the thousands
                         of intricate parts that make up the LHCb detector.
                             One set of cooling valves looked as if it could
                         be reached from a platform above. But the
                         platform was just far enough away that “you would
                         need one-meter arms” to grab the valves,
                         says LHCb Installation Coordinator Rolf Lindner—
                         feasible for 7’6” basketball player Yao Ming,
                         perhaps, but not for the average particle physicist.
                         What’s more, when contractors discovered
                         they couldn’t reach the valves from above, they
                         started using the cooling pipes that ran beneath
                         the valves as a ladder, which was not good for
                         the equipment.
                             LHCb needed a real ladder, one that couldn’t
                         be found at a hardware store. So the LHCb
                         experimental area team specially designed a lad-
                         der topped with a platform. Contractors built
                         the parts from aluminum, a metal immune to the
                         high magnetic fields that will be generated by
                         LHCb’s powerful dipole magnet. Finally the parts
                         were lowered into the cavern, drilled with a few
                         holes and bolted into place.




Photo courtesy of CERN

                         21
CMS: Drip, drip, drip
For the CMS experiment, leaky pipes were a prob-
lem. As Gerd Fetchenhauer of RWTH Aachen
University in Germany put it, “Sometimes you see
water on the floor and you think, ‘Where the hell
is that coming from?’”
     Chasing down the leaks is no easy feat. CMS’s
16 main cooling circuits deliver water to 3500
locations around the cavern, Fetchenhauer says.
Puddles on the cavern floor may have started
as drops trickling from anywhere in the 49 feet
of detector equipment above. “The tricky part
is really to guess where it came from and where
it leaked into on its way,” says CMS Experimental
Area Manager Martin Gastal.
     Finding the leaks is the job of a team of plumb-
ing private eyes from the Polish company ZEC.
The team has been working at CMS for seven
years, first laying 130 miles of copper and
80 miles of stainless steel pipe for gas and cool-
ing, then connecting individual detectors
to their plumbing lines, and now fixing leaks in
plumbing that was installed before pressure
testing—which reveals weak spots in the piping—
became mandatory.
     The plumbers are aided by a monitor that
measures the outgoing water against incoming
flow. An easily accessible problem can be
fixed in a few minutes with standard plumbing
adhesives and thread-sealing tapes. More chal-
lenging fixes can take two days.
     That was the case for a leak that sprang dur-
ing a test run of the CMS detector. CMS is
arranged in 11 massive slices, each weighing up
to 2000 tons, mounted on special pads that
generate a cushion of air and allow them to easily
slide across the floor. When the detector is in
operating mode, the slices are jammed together
with just a few centimeters between them.
When workers need access, the slices can be
pulled up to three meters apart.
     This particular leak, caused by vibration in the
cooling pipes, appeared high in one of the
five inner slices. Four slices had to be moved so
plumbers could ride up in the basket of a cherry-
picker crane and seal a fitting.




Photo courtesy of CERN



                                                  22
ATLAS: Practicing on rays from space                       half of the electromagnetic calorimeter,” says
In experiments that push the limits of technology,         CERN’s Martin Aleksa. “However, on the week-
glitches are inevitable during the first years             ends, we took data with the full system, and the
of operation. ATLAS physicists took advantage of           full system worked.”
the shutdown to fix problems with the calo-                    Taking cosmic-ray data allows the subdetector
rimeter systems, subdetectors that absorb particles        systems to sync up with changes to ATLAS
and measure their energies.                                software, as well as adjust the timing and align-
    An American company refurbished a set                  ment within a subdetector—both critical to
of power supplies associated with the electro-             precisely measuring particles as they pass through
magnetic calorimeter over the winter, and                  multiple systems. Eventually all repairs were




                                                                                                                     symmetry | volume 06 | issue 04 | august 09
scientists began reinstalling them in the spring.          complete and ATLAS once again operated as a
Meanwhile, the hadronic calorimeter, which                 whole with all detector groups running simulta-
measures the energies of proton-like particles,            neously, checking timing and alignment against
needed work on 80 of its 256 “drawers.” Each               one another.
drawer contains sensors and electronics that
independently process data from the calorimeter.           Improvements: A never-ending quest
During testing, physicists had noticed that                The unexpected delay in the start-up of the Large
some of the channels sent out incorrect data or no         Hadron Collider was far from a blessing in
data at all; with repairs complete, more than 99           disguise. The detectors were fully prepared for
percent of the subdetector now functions correctly.        collisions at the time, and the collaborators
    Even as repairs were going on, ATLAS’ sub-             hungry for data to analyze in search of physics
detector systems stretched their legs with                 discoveries. They’re hungry still. But they know
weeks of practice in gathering data from cosmic            that a big accelerator is always something of a
rays—high-energy particles from outer space                work in progress, and they expect to keep
that constantly bombard the Earth, and the LHC             maintaining, building on, tweaking, and improving
experiments.                                               the LHC detectors right up to the end of the
   “For most of these runs, we worked with only            collider’s long lifetime.



                                                                      Photo: C. Marcelloni, ATLAS experiment, CERN




                                                      23
Dancing with

Dancer Ben Wegman blends into the evening fog on the CERN
campus, where he joined Liz Lerman to do research for her
upcoming performance piece. Photo: Amelia Cox




                                                            24
physicists



                                                symmetry | volume 06 | issue 04 | august 09
For her latest work, choreographer Liz Lerman
took members of her dance troupe to CERN,
where they reveled in the fog, danced in the
aisles and found inspiration in wide-ranging
conversations with scientists.

By Calla Cofield




                           25
         Liz Lerman is an accomplished choreographer,                  particle physics lab near Geneva that is home to
         writer, performer, educator, and artist whose                 the LHC, Lerman brought with her a small team
         laurels include the American Choreographer                    of dancers who spoke with scientists and even
         Award, an honorary doctorate from Williams                    performed a few dances in the LHC tunnels and
         College, Washingtonian Magazine’s 1988                        work spaces. Lerman spoke with symmetry’s
         Washingtonian of the Year and a 2002 MacArthur                Calla Cofield about her impressions of CERN’s
        “Genius Grant” Fellowship. She founded The                     huge scientific community, whether symmetry is
         Liz Lerman Dance Exchange, based in Takoma                    beautiful, and why dancers and physicists share
         Park, Maryland, in 1976. Since 2006, the group                a certain kinship. She remains in contact with
         has traveled throughout the country performing                a number of scientists as she begins to shape the
         a multimedia dance production titled Ferocious                piece, set to debut in the fall of 2010, that she
         Beauty: Genome. With Gregor Mendel as a lead-                 tentatively calls Matter of Origins.
         ing character, this work examines the nature
         of discovery and the implications of present-day              Q. What made you choose particle physics and
         research in genetics.                                         the LHC for your next project?
            Now, Lerman and her company are producing
         a piece that explores the question of how                     A. Well, that completely took me by surprise.
         things begin, and are advancing their research                I wasn’t looking, and I wasn’t imagining it at all.
         through conversations with specialists in                     I was approached by Gordy Kane, a physicist at
         a variety of fields, including scientists at the Large        the University of Michigan and director of the
         Hadron Collider.                                              Michigan Center for Theoretical Physics, to at
            On her second trip to CERN, the European                   least think about [going to CERN] and I decided
                                                                       to go take a look. Once we went, then a whole
                                                                       lot of things took over.
Members of the Liz Lerman Dance Exchange in Ferocious Beauty:
Genome, a science-based, multimedia performance piece. Photo               A long time ago, my dance company spent
at top: Michael Mazzola; photo at bottom: Kevin Kennefick              almost two years going back and forth to a ship-
                                                                       yard—the Portsmouth Naval Shipyard—for a big
                                                                       community arts project with multiple outcomes,
                                                                       including a finalé of 700 participants.
                                                                           And in some ways CERN reminded me
                                                                       of that: this huge complex, this enormous number
                                                                       of people working together toward something
                                                                       much bigger than themselves. It’s a very inviting
                                                                       kind of environment just to see the thousands
                                                                       of stories that are there.
                                                                           I think the other thing is, as a dancer and
                                                                       choreographer I’ve spent a tremendous amount
                                                                       of my life defending something that’s very hard
                                                                       to see. I mean people see dance, they see the
                                                                       dancers, but they have trouble understanding
                                                                       why it’s valuable, what you’re trying to say. And
                                                                       in some ways I feel that’s reflected in what
                                                                       I learned initially from the physicists. It’s very
                                                                       abstract, it’s hard to see, people have trouble
                                                                       trying to understand it, it has tremendous value
                                                                       to us as a civilization but it’s not easy to explain.
                                                                       So I think I felt a certain kindred spirit even though
                                                                       our fields are obviously quite distinct.

                                                                       Q. What was the response from the physicists
                                                                       at CERN when you talked to them about
                                                                       your project?

                                                                       A. I think people like to talk to artists, and the
                                                                       scientists are mostly very happy to speak. A lot
                                                                       of times they tell us things that they think we
                                                                       want to hear. They tell us things that they think are
                                                                  26
“As a dancer and choreographer I’ve spent a tremendous
 amount of my life defending something that’s very hard to see.”
physical, or things that they think would look                   Q. Were there any other big ideas that stood
beautiful as a dance. But sometimes they’ll just                 out to you when you talked to these scientists?
look at you with great bemusement and say, “Well,
what’s on your mind? What do you want to know?”                  A. One of the things we’re interested in is what
    But what was really fun at CERN was that the                 are the questions they’re asking, and which
minute Ben Wegman, the dancer, was down in                       of those questions have real, enormous resonance




                                                                                                                                              symmetry | volume 06 | issue 04 | august 09
the ATLAS cavern and he was dancing, just spin-                  for the public? For example, they think they’re
ning, work stopped. People started flashing                      going to understand more about the big bang, and
their camera phones and we understood later that                 I think the public is just incredibly interested in
there had been an electric current through the                   that. I think how we see our beginnings really
whole place. Word spread that there was a dancer                 affects us emotionally, intellectually, spiritually,
down in the cavern. I think people got really                    in all kinds of ways.
excited. And of course they laughed and hooted                       Last time I saw Gordy I said, “What happens
and all that, but we’re used to that. That was                   if you don’t find [the Higgs boson]?” He’s
very interesting.                                                convinced they’re going to find it, and I said what
    The other thing that I love—and maybe this is                if you don’t? Who’s right, who’s wrong, and do
why it’s interesting for scientists to spend time                you have to put some ideas to bed then? And does
with us—is when you have to explain yourself to                  that mean that people who spent 20 years
somebody who doesn’t know any of your jargon,                    looking for it feel regret or shame, or is this the end
you are forced to try again. And when you try                    of an idea? I don’t know if regret is part of
again, then I think sometimes you stumble into                   a scientist’s world. In science, what happens when
a way of describing, modeling, or actually under-                things turn a corner?
standing yourself better. I know that’s true                         One of the conversations we got into a lot, for
for me when I try to explain myself to people who
don’t know what I'm doing. I think that happens for                 Experimental physicist Maria Spiropulu, left, illustrates ideas for Liz
the scientists too. And you know, we ask very                       Lerman over brunch in Geneva. Photos: Amelia Cox
challenging questions because we have a way
of thinking and seeing that’s different.

Q. What were the challenging questions?

 A. I’ll tell you a conversation I’m in the midst of with
 Gordy. I keep hearing about symmetry. I read
 things by the physicists and they talk about
 symmetry and supersymmetry and the elegance,
 simplicity, beauty, and aesthetics of symmetry.
 Well, I wrote Gordy and I said for me this is a prob-
 lem, because for me symmetry is not beautiful:
 symmetry suggests amateurs, symmetry suggests
 static. So now we’re in a big discussion about that.
     Meanwhile, with that conversation in mind,
 I went to Spain, where my daughter is spending
 her junior year, and we went into Cordoba. And
 we saw this Islamic influence in the architecture
 there and in these tiles that are all symmetric. And
 I got interested because I’m in the middle of
 this debate with Gordy and I actually liked the
 symmetry I saw there. I picked up a book on
 Islamic art and symmetry and the author says the
 Islamic symmetric design is an expression of the
“essential relationships that lie beneath the visual
 surface of the world.” So I am delighted to go down
 that path for a while, to study these ideas and to
 see where they go and to compare the language
 to what I'm hearing from the physicists. Whether
 this shows up in the piece or not I don’t know, but
 we are working hard on symmetry right now.
                                                            27
         some reason, was physicists’ spiritual feelings.              scientists are thinking about it. They don’t dismiss
         They kept bringing this up. It was so interesting.            that question. I find that most professionals feel
         I didn’t ask a question about that but it just kept           a responsibility to the issues that their field
         coming up, what the state of their belief was.                has to address or is causing them to address. But
         And in fact I told them an old story, a Jewish cre-           most of our professions don’t value our helping
         ation story that’s not the biblical one you usually           make that work for the public. It’s as if you’re more
         hear; it’s from the Midrash, one of the Jewish                of a professional if you stay disengaged from the
         alternative stories to the Bible. God wants to                public’s need. And I find that very peculiar, but
         create the world but God can’t because God takes              I find that’s true across the board. I’d love to see
         up too much room, so God contracts in order                   that change.
         to make room for the world. That’s a shorthand
         version. And the physicists just loved that.                  Q. In some of the early dancing that your group
                                                                       has done for this project, you have people
         Q. What did people have to say about spirituality?            representing particles. What does that do to our
                                                                       notion of a particle?
         A. There was a wide range, from cynicism to com-
         plete spiritual belief to people who actually said            A. It’s one of those interesting things where we
         straight out, “My science is my religion, but let me          realize that all language is symbolic. Because
         point out all the parallels.” And then they would             even calling it a particle, you might think of a dust
         point out all the ways in which CERN was like                 particle or a dirt particle or whatever is in peo-
         a church, and who was playing what role.                      ple’s imaginations. I ran into this with genomics
             I think I did ask them if they were looking at the        stuff. They talked so much about protein folding,
         big bang, how they were helping the public                    and we got so into folding and had such a good
         through questions. You know, did they feel any                time with all this folding stuff. And then I finally
         responsibility about people who come with their               saw an animation of what people thought
         religious beliefs about that? And in fact the                 protein folding was, and it’s not folding at all! It’s
                                                                       more like intense wrapping. I would never call it
Ben Wegman moves down an aisle of server racks at CERN’s               folding. That’s when I realized that our language
Computer Center. Photos: Amelia Cox                                    is problematic, too. It’s not just that dancing is
                                                                       an approximation, but the language is an approxi-




                                                                  28
“For me, symmetry is not beautiful: symmetry suggests
 amateurs, symmetry suggests static.”
mation unless you can see the actual thing,                   that inspired you, when did it happen, why. And
and with a lot of this stuff you can’t. And that got          imagine the catalog of incredible discoveries
me very excited, actually. I thought for a while              we would hear. Or, we saw this guy mowing the
that I could make a dance about dueling meta-                 lawn while we were there, and we thought
phors, because people say such different things               wouldn’t it be interesting to interview the guy who
when they’re trying to explain something that                 mows the lawn? What do you suppose he’s




                                                                                                                     symmetry | volume 06 | issue 04 | august 09
you can’t see.                                                thinking? You think he’s worried? (laughs) You
                                                              think he wonders if, you know...
Q. What else would you like to see happen at
CERN in terms of artists going there?                         Q. Does he wonder if they’re going to create a
                                                              black hole?
A. I wish there was enough money for CERN to
have a whole group of artists there, because                  A. You know, he may embody some of those
there are so many good stories to be told. It just            things we keep hearing about, I don’t know.
wouldn’t even cost that much to have an official
storyteller in residence. My husband is a story-              Q. Are you going back to CERN again?
teller; that’s his job. He collects stories and he
tells people stories and he went with me on both              A. I hope to. I want to very, very much. We hope
these trips [to CERN], and unlike my work, which              to have a three-week residency. But right now
requires lots of bodies and lots of tech, he                  the funding in our world is really hard hit. We need
just pulls a stool out, sits down, and starts talking.        to do it, but I don't know if we’ll get to.
    The thing is, there’s so much to be learned.
Everybody working at CERN has an interesting                  Q. The performance is set to premier in the fall
story. Even if you just started with “Why are you             of 2010. Will you perform it at CERN?
here?” or “How did you get here?” or “Who’s the
person in your life who helped you understand                 A. We would love to take it to CERN, and we
that this is where you needed to be?” we would                talked to a festival held about ten to 15 minutes
learn so much about teachers! We would learn                  away from CERN where we could perform it. Or
probably all there is to know about good teachers             we could take it apart and do pieces of it around
if we asked everybody at CERN who’s the one                   CERN. But we’d love to perform there.




                                                         29
gallery: takuya uruno


Bam! Sproing! Gyaaa!
In the Web series Kasoku Kids, a Manga artist delivers
particle physics with feeling.

By Nicholas Bock




                                            30
                                                                                                    symmetry | volume 06 | issue 04 | august 09




In Japanese, Takuya Uruno’s first name means “pioneer.” In his 25-year career as a pro-
fessional Manga artist, Uruno has been steadfast in living up to the title. He has spent only
five years working on the popular serials that Manga is most commonly associated with and
another 20 working in advertising and public relations, trying to find ways that Manga can
function as something more than entertainment.
   “Although Manga in public relations is similar to the ordinary Manga in technique and
theme, it requires a different set of skills,” he says. “My mission is to explore Manga’s new
potential and to pioneer a new field. I am quite a rare case even within this country in which
Manga is very big.”
    When KEK Communications Director Youhei Morita asked Uruno to help design a suite
of kid-oriented pages for the KEK Web site, it was the perfect opportunity to push Manga’s
role even further. KEK is the High Energy Accelerator Research Organization in Tsukuba,
Japan. Working closely with scientists at the laboratory, Uruno came up with a series of episodes


                                               31
gallery: takuya uruno


      in which four children working on a science fair project visit KEK and meet two physicists,
      who take them on a tour.
          The goal for Uruno was not to teach specific physics concepts, but to captivate his audience
      and to generate interest in science—to get people interested in high-energy physics and
      what physicists at labs like KEK do.
         “I tried to depict children learning physics, rather than physics studied by children,” he says.
     “Some are skeptical, others holding up their hopes, and they all come to KEK. Their
      encounter with doctors who are seriously searching for the secrets of the universe excites
      their interest in science.”
          Uruno found that Manga was extremely well-suited to navigating the conceptually complex




                                                      32
                                                                                                   symmetry | volume 06 | issue 04 | august 09




waters of particle physics. Unlike reading a textbook, he said, Manga provides readers
with a more immersive experience, enabling them to make stronger connections with
different ideas.
   “It is easier to understand complicated matters when one projects his or her feelings
onto others and explores the experience,” he says. “The characters are exactly for that purpose.
The readers relive the drama, and the emotions can improve their understanding.”
    Other times Uruno had to defy Manga orthodoxy, finding new ways to present the topic
without inadvertently limiting readers’ conceptions—something that can be hard to do when
trying to graphically represent things that have never been observed.
   “To depict a single elementary particle, I refused to go into the traditional Manga style in
which animals or ordinary matters are personified,” he said. “I presented it instead to be
something obscure and vague so as to let the readers explore the real mysteries of the
smallest entity.”


                                              33
day in the life: hitoshi murayama




The Emperor’s Tea
    When I assumed the position of director of the             learned what we were not supposed to do. No
    Institute for the Physics and Mathematics of the           photos of the Imperial family and no touching, even
    Universe (IPMU), my smart-mouthed friends                  handshakes. But we could have a brief conver-
    joked that I became the Director of the Universe.          sation. Another useful piece of information was
    They didn’t imagine that I was going to meet               that the guests arrive in cars, not on foot. My
    somebody whose title would have made him                   wife, who still lives in our home in Berkeley, came
    a deity less than seven decades ago.                       over just for this occasion, and we got into an
        In the heart of the concrete jungle in downtown        orange cab. The driver told us that he had driven
    Tokyo, there is a meticulously cared-for Akasaka           into the garden only twice in his 20-plus years
    garden, off-limits to the general public. It is            of service. He proudly displayed on his dash the
    a part of the Akasaka Estate that serves as a resi-        permit we had received with the invitation. As
    dence for the Japanese Imperial family members,            the cab approached the entrance of the garden,
    spanning 135 tranquil acres in the midst of the            we couldn’t help notice that all the other cars
    buzzing metropolis. Twice a year, the Emperor and          around us were black limos. When we arrived at
    Empress invite about 2000 guests to this beau-             the drop-off, we exhaled a sigh of relief upon
    tiful garden to honor their service to the nation.         finding at least two more brightly colored cabs.
    This spring I was one of them, thanks to a strong              The party started with a peaceful performance
    recommendation from the Ministry of Education              of ga-gaku, an adagio-paced style of music
    that funds IPMU. I was flattered, and scared.              more than a millennium old. We enjoyed charac-
        For a person who spent 14 years on the                 teristically understated yet high-quality hors
    Berkeley campus in jeans, the first reaction to the        d’oeuvres and drinks. Looking at the name-tags
    invitation card decorated with the Imperial                others wore, however, we felt completely out
    emblem was, “Oh my goodness, what shall I wear?”           of place. Most others clearly deserved the honor:
    Fortunately, according to many blogs written by            retired high-level government officials, members
    former invitees that my wife found, a regular dark         of the Congress, governors, mayors, and diplomats
    suit would do the job. I had exactly one. We also          from other countries clad in their ethnic dresses.
                                                          34
                                                          Images courtesy of Hitoshi Murayama


                                                                                                symmetry | volume 06 | issue 04 | august 09




“I told the emperor that I am trying to attack the
             mysteries of the universe, and am building
       a new international research institute.
                        He wished me good luck.”




                            35
day in the life: hitoshi murayama

                                    We could spot a few academics, however.
                                I knew exactly two other invitees: Makoto
                                Kobayashi and Toshihide Maskawa. They had just
                                won the Nobel Prize in Physics last winter for
                                their theory that explains why the world of antimat-
                                ter is not the exact mirror of the world of matter we
                                live in. Never mind that their theory does not
                                explain why we do not have to worry about any
                                antimatter around us. If you believe Dan Brown’s
                                Angels & Demons, our existence is threatened by
                                antimatter in the real universe, where we can’t
                                count on Tom Hanks to save the day. I actually
                                think that ghostly neutrinos played the role of
                                Camerlengo, who took the antimatter away on
                                a helicopter. Unlike in the movie, it must have
                                happened when the universe was less than 10-25
                                seconds old, removing most of the antimatter so
                                it would never play a role in our everyday lives.
                                    About an hour later, the Japanese anthem that
                                hails the reign of the Emperor filled the garden,
                                announcing that the Imperial family had arrived
                                and had started to walk around the lake. Everybody
                                made a long line around the lake, waiting for
                                them to pass by each one of us.
                                    Physicists are well known to run quick-and-
                                dirty math. The whole walk by the Imperial family
                                was scheduled for less than two hours. For 2000
                                attendees, each of us gets about three seconds.
                                I wondered what words I could possibly mouth
                                that were worthy of their precious seconds.
                                    We had waited for about 90 minutes when
                                a man looking like a butler told us that our time
                                was nigh. We became stiff.
                                    We saw the Emperor and Empress approach-
                                ing us. They had an aura of style and elegance,
                                and were surprisingly friendly. They studied each
                                one’s name-tag, and spoke appropriate words
                                of appreciation.
                                    To a retired officer of the Self Defense Army,
                                they thanked him for the important service. To
                                the head of a fire department, they encouraged
                                him to keep up the good work. All their remarks
                                were right on, yet brief. In response, nobody said
                                much beyond a “thank you” and a bow. And they
                                steadily, but not hastily, moved on.
                                    When the Emperor approached me, he stared
                                at my name-tag. I realized I had an amusing
                                advantage. My title was long, and it did not make
                                sense right away. He then asked me what I did.
                                An opportunity for a conversation! I told him that
                                I am trying to attack the mysteries of the universe,
                                and am building a new international research
                                institute. He wished me good luck.
                                    The Empress followed and asked what the
                                name of the institute meant. In addition to
                                answering her question, I took the opportunity to
                                tell her that we did not understand 96 percent
                                of the universe. She looked genuinely surprised.
                           36
    The best moment was when the Crown Prince
came by. I knew that the previous Emperor




                                                            symmetry | volume 06 | issue 04 | august 09
studied biology, and even discovered new species
of hydrozoa. To my pleasant surprise, Prince
Naruhito was interested in astronomy. He points
a telescope at the sky, gazing at the stars, and
tracks comets. He was excited about the universe.
And of course I told him that we were trying to
understand dark matter that we cannot see in the
telescope. He was quite amused.
    Princess Takamado also wanted to know what
I did. Having learned that I did research in
physics, she wanted to know what a physicist talks
about at home. She looked genuinely relieved
to hear that a physicist talked about kids, money,
and music.
    I suspect it is a mentally demanding job to
meet 2000 strangers and figure out what appro-
priate words to give. They also maintain attractive
smiles throughout their long walk. I’m convinced
I cannot do this at all. This realization made
me appreciate the whole experience all the more.
    After the Imperial family retired, the crowd
started to disappear. We walked round the lake
and enjoyed the beautiful garden. It was
a peaceful moment in a beautiful place. After trying
to soak the whole thing in as much as we could,
we walked out of the garden to the nearby
Metro station.
    Back to normal life. But I smiled at the thought
that the Imperial family might be discussing the
nature of dark matter.
                                                       37
accelerator applications

                                Heart valves get                                          material for dental implants and artificial hips,
                                silver linings                                            to help new bone attach. But the gold ions just
                                                                                          made the carbon smoother.
                                Physicists at Alabama A&M University hope to                 “That was about a year of frustration,”
                                improve the safety of artificial heart valves by          Zimmerman says.
                                forming them from a material bombarded with                   Then, in 2000, the physicists met Ismet Gurhan,
                                silver ions from a particle accelerator.                  a young biologist from Turkey. She suggested
                                    Artificial valves should last a lifetime, so they     that they try firing silver nuclei into the material
                                have to be made from durable material. In the             instead. Silver has a reputation for being anti-
                                1970s, physicist Gwyn Jenkins at Alabama A&M              microbial and might repel the cells, she told them.
                                developed a robust material similar to the one               “That changed our research profoundly,”
                                NASA uses to protect space shuttles during                Zimmerman says.
                                reentry. Called glassy polymeric carbon, it is light,         The ion accelerator at Alabama A&M can
                                withstands high temperatures, and is well-                boost silver ions to an energy of 5 million
                                tolerated by the human body.                              volts. That’s 50,000 times as high as the voltage
                                    Jenkins started a company to make artificial          running through a household iron. When
                                heart valves from GPC, and was soon joined by             fired through a vacuum into the glassy polymeric
                                physicists Daryush Ila and Robert Zimmerman.              carbon, the silver ions penetrate a distance
                                    Even though GPC is body-friendly, it faces            100 times smaller than the diameter of a
                                the same problem as other implant materials: The          human hair.
                                body treats them as invaders and surrounds them              “For materials that’s a long distance,”
                                with tissue to seal them off.                             Zimmerman says. “That can’t be done with
                                   “Say a rose thorn gets under your skin,”               chemistry.”
                                Zimmerman says. “If you don’t pull it out, it will be         They sent the treated carbon samples to Turkey,
                                encapsulated and come out later. There are                where Gurhan verified that cells would not touch
                                even cases of soldiers who have been shot having          them. “The cells were adamant,” Zimmerman says.
                                the bullet encapsulated enough that the person           “They didn’t like the implanted silver.”
                                isn’t exposed to toxic lead.”                                 Yet the small amount of sequestered silver
                                    This tissue build-up is dangerous only if pieces      should have no effect on the body’s acceptance
                                of tissue come loose; some cardiologists worry            of the heart valve, the researchers say.
                                that they might block an artery, causing a dis-               The physicists are still investigating why the
 Photo: Reidar Hahn, Fermilab




                                tressing or fatal problem. So Ila, Jenkins, and           silver stops cell growth. The next step belongs
                                Zimmerman set out to modify GPC so it would               to the biologists, who will determine if the
                                hold tight to the tissue around it.                       silver-implanted valves are safe enough to heal
                                    First they bombarded it with gold particles from      a human heart.
                                an accelerator to make it rougher and easier              Kathryn Grim
                                for cells to grip. Doctors use this sort of rough
                                                                                                                                                 symmetry | volume 06 | issue 04 | august 09




                                Heart valve provided by St. Jude Medical.




                                                                                        38
logbook: weak neutral current

                                                                                                                            Outgoing
                                                                                                                            neutrino




                                                                                                                       e+


                                                                                                        e+        e–

                                                                                                                            Shower of
                                                                                                         e–   e–            particles due to
                                                                                                                            bremstrahlung

                                                                                                                       e+

                                                                                                              e
                                                                                                              –




                                                                                                                            Collision
                                                                                                                            point
 Image courtesy of CERN




                                                                                                                            Incoming
                                                                                                                            neutrino




                          The Gargamelle collaboration                                              at the European laboratory CERN began
                                                                                                    operating its bubble chamber in the
                          early 1970s, shooting neutrinos through 12,000 liters of Freon, a heavy liquid. Cameras took photos from various
                          angles every time a pulse of neutrinos traversed the five-meter-long bubble chamber.
                              By the summer of 1973, the collaboration had taken more than 700,000 pictures and had distributed them
                          among the seven participating institutions for processing. An army of workers, most of them women,
                          scanned the film for particle tracks—bubbles left in the wake of charged particles. Scientists then classified
                          the tracks and looked for signs of unexpected types of neutrino interactions.
                              This picture, taken and scanned in 1972, caught the attention of scientists of the analysis group in
                          Aachen, Germany, and word of it soon spread across the entire collaboration. The neutrino, which leaves
                          no track because it has no electric charge, entered the bubble chamber from the bottom of this image
                          and hit an electron.
                              Unlike all other neutrino events seen before, this collision did not transform the incoming neutrino into
                          another type of particle. Instead the neutrino remained a neutrino after hitting the electron and propelling
                          it forward, slightly to the left. Moving through the liquid, the electron slowed down and emitted light, known
                          as bremsstrahlung. This light, in turn, created the electron-positron pairs visible in the photo, making the
                          initial electron easily identifiable.
                              So why did scientists get excited? For a long time, physicists had thought that neutrino interactions would
                          always change the nature of the interacting neutrinos. Those processes, which involve the weak force,
                          are called charged-current interactions, because they are mediated by W bosons with either a positive
                          or negative charge. But in the late 1960s and early 1970s, a group of theorists developed a new mathematical
                          description for neutrino interactions that required neutrinos to interact weakly through a neutral current, as
                          well. This interaction would be mediated by the exchange of a particle without electric charge, later named
                          the Z boson.
                              Subsequent results from the Gargamelle experiment firmly established the existence of the weak neutral
                          current. The September 3, 1973 issue of Physics Letters featured two back-to-back papers by the Gargamelle
                          collaboration, one on neutral-current interactions based on the electron event shown here, the other on
                          neutral-current interactions of neutrinos with nuclei. In 1974, the E1A experiment at Fermi National
                          Accelerator Laboratory in the United States confirmed the discovery. The mathematical framework that
                          predicted the weak neutral current became known as the Standard Model of particles and their interactions.
                          Kurt Riesselmann
    Symmetry
    A joint Fermilab/SLAC publication
    PO Box 500
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    Batavia Illinois 60510




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explain it in 60 seconds




                                        Cherenkov light                       appears when a charged particle travels
                                                                              through matter faster than light can.
                                        This effect is the optical equivalent of a sonic boom, which occurs, for
                                        example, when a jet travels faster than the speed of sound.
                                            But how can a particle go faster than light without violating the laws
                                        of physics? The speed of light in a vacuum is the ultimate speed limit:
                                        300,000,000 meters per second. It’s thought that nothing can travel faster.
                                            However, light slows down when it goes through water, glass, and
                                        other transparent materials—in some cases by more than 25 percent.
                                        Hence a particle can slip through material faster than light does, while
                                        at the same time staying below the speed of light in a vacuum.
                                            When this happens, a particle emits bluish Cherenkov light, which
                                        spreads out behind it in a hollow cone that is shaped like the cone of
                                        a sonic boom. This light gives the water surrounding a nuclear reactor
                                        core its distinctive blue glow.
                                            Scientists build telescopes to gather Cherenkov light emitted by cosmic-
                                        ray and gamma-ray showers in the Earth’s atmosphere. Neutrino
                                        physicists embed hundreds of light-sensitive detectors in large volumes
                                        of water and ice to record Cherenkov light from muons and electrons,
                                        which emerge when neutrinos crash into atoms. The Cherenkov light
                                        recorded with such devices helps scientists identify particles and
                                        determine their energies.
                                        Michelangelo D’Agostino, University of California, Berkeley

				
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