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					“Diquarks,Tetraquarks, Pentaquarks
          and no quarks”

The meson landscape

Scalars and Glue in Strong QCD

New states beyond

Weird baryons: pentaquark problems




                                     Frank Close
                                     ICHEP04
                            (cc*)

                                      1D: 1-   3772


2S: 1-   10023 3686

                           9913     3556
                      2+


                      1+   9893     3510


                      0+   9860 3415

1S: 1-   9460 3097
                                           (cc*)

                                                        1D: 1-            3772


2S: 1-   10023 3686

 Glue-gamma                              9913       3556
 interference -90 degrees(Wang)   2+
                                                                  Radiative E1
 And 2S-1D mixing (Rosner)                                        transitions
 Solution to suppressed                                           precision beyond
 hadronic modes                   1+     9893       3510          simple cc*
 BES; CLEOc


                                  0+     9860 3415

                                       Hadronic decays entrée
1S: 1-    9460 3097                    to gluonic light hadrons
                                       1++ to pi and exotic 1-+
                                       (hybrid) BES;CLEOc
                I=1 vector : I=0 JP = 2+ 1+ 0+ (nn* ss*)


                                             1D: 1-   1700

2S: 1-   1460

                                2+   1270/1525

                                1+   1285/1530

                                0+


1S: 1-   770
                I=1 vector : I=0 JP = 2+ 1+ 0+ (nn* ss*)


                                              1D: 1-   1700

2S: 1-   1460
    qq* seed dominates                1270/1525
    If no S-wave meson           2+
    channels are open.

    S-wave hadrons hide qq*      1+   1285/1530
    Production channels
    give different impressions
                                 0+
    of Fock state
                                 Big problem for scalars
1S: 1-   770                     which couple to pi pi etc
                                 in s-wave even though qq*
                                 is in p-wave
 6              I=1 vector : I=0 JP = 2+ 1+ 0+


                                                 1D: 1-   1700

2S: 1-   1460

                                2+   1270/1525

                                1+   1285/1530

                                0+ 1370/1500/1710/1790


1S: 1-   770
  7             I=1 vector : I=0 JP = 2+ 1+ 0+


                                                 1D: 1-   1700

2S: 1-   1460

                                2+   1270/1525

                                1+   1285/1530

                                0+ 1370/1500/1710/1790

                                      980/600
1S: 1-   770
 8              I=1 vector : I=0 JP = 2+ 1+ 0+


                                                 1D: 1-   1700

2S: 1-   1460

                                2+   1270/1525
     ? qq* + Glueball
     Lattice G =1.6 \pm         1+   1285/1530

                                0+ 1370/1500/1710/1790
                                 0+
                                      980/600
1S: 1-   770
9

    Scalar Glueball and Mixing



        s
    G
        n
10
         Scalar Glueball and Mixing
     a simple example for expt to rule out

                 Meson


     s           1710

     G           1500
     n
                 1370
11
      Scalar Glueball and Mixing
     a simple example for expt to rule out

                Meson     G       ss*    nn*

                1710     0.39    0.91    0.15
                                                 0- 0-
     s                                           meson
                                                 decays
                1500    - 0.65   0.33   - 0.70   LEAR/
                                                 WA102

     n          1370    - 0.69   0.15   0.70
12




     >1 billion                  1000 per meson
     Coming soon
     from BES and
     CLEO-c
                         A flavour filter for
                            0++ 0-+ 2++ (and 1++)
                         mesons glueballs et al
         Challenge:
         Turn Lattice QCD Glueball spectrum into physics
  13            I=1 vector : I=0 JP = 2+ 1+ 0+


                                                 1D: 1-   1700

2S: 1-   1460

                                2+   1270/1525
   ? qq* + Glueball
                                1+   1285/1530
     [qq][q*q*]
     seed and/or                0+ 1370/1500/1710/1790
                                 0+
     S-wave mesons
                                     980/600
1S: 1-   770
   Production chooses easiest route:
       interpretation needs care
e.g.          K       gamma
       phi
                           S wave KK
                           into 0++ long range wavefunction
              K            Says little about short range QCD
                           wavefunction

  980 (uu*+dd*)ss*         KLOE
  980 (uu*- dd*)ss*


  Contrast Xi_c(3400) \to f0(980)f0(980) (BES)
  and Z decays which feed f0(980)
  via “easiest” qq* like other hadrons
15




        New states
     outside the quark
          model:

 cc* X(3872) anomalous charmonium
16
         B decay = a new source of charmonium

A new narrow charmonium state

Charmonium candidates
2- 3- radial1+
are narrow below DD*

Mass, width, angular dist etc
all inconsistent with cc*




Standard cc* theory wrong?
Or is X(3872) not simple cc*?
DD* molecule “tetraquark”
                                     Close+Page
                                     Tornqvist
Mass same as neutral threshold       Swanson
to better than 1 in 10,000

cuc*u* S-wave JPC = 1++
= isospin maximally broken




  Also psi omega: Belle
  Test: X \to K+K-\pi>> K0K0\pi

  CLEOc/BES test for 1++ 3550 also

                                                  Rho?
18
      S-wave meson-meson beats P-wave qq* (continued)

     cc*1++ 3550; 1++* 3950:          P-wave cc*
                                                            Mass coincidence
     DD* (neutral) threshold                                only happens with
                               S-wave 1++ mesons            Charm, not strange
     Psi rho; psi omega                                     or bottom

                        psi                   Energy degeneracy will drive
D                                             this >> model details.

                                              Psi rho:psi omega \sim 1
D*                       uu* vector           Deviations = dynamics

                                              Specific model: Swanson
 D                       D*
               pi
                               Decays driven by meson-meson wavefunction
D*                       D
                               Production by cc* residue: like psiprime
19



     X(3872) summary




                  cc* 1++ seed
          Meson-meson S-wave dominant
20        A Baryon analogue from BES ?     (Shan Jin talk)


      S-wave baryon-meson beats P-wave qqq

 Baryon S_{11} is qqq p-wave but prefers N-eta
 Rescatters to K Lambda (e.g. BES, previous talk)

            K                  eta


      Lambda                   N



     Psi to gamma p pbar enhancement/bound state also?
22



        New states
     outside the quark
          model:

       cs* (2317;2460;2635)
23
           Novel states in
• 0+        2317                       Isospin violation
• 1+        2460                       as below DK threshold

          ultralite cs*; DK molecule


• J^P=?… 2632
      Narrow. Anomalous decays “anti” phase space

     cs* 1- radial (nodes); mix with ^3D_1 = X
     cs*uu* (Iso violation); = X
     = artefact ?
                                                              25
Why in cs*?

                 (also M.Nowak et al, HADRON2003)




                                        1+             2560
                                              243MeV
              Which 1+?
26




     D*K

     DK
27 S-wave meson-meson beats P-wave qq* (continued)

   Whatever makes scalar f_0(980) light (= just below KK)
   (compared to qq* p-wave)

   Probably makes scalar 2317 light (= just below DK)
   (compared to qq* p-wave)

   …and 2460 axial light (just below D*K)
   Production by easiest route: cs* residue
   Decays driven by di-meson DK D*K

   TEST: 1+ \to 0+ \gamma (M1)

   D*K \to DK \gamma = D* \to D \gamma
28

Another novel state in

 • J^P=?       2632
     Narrow. Anomalous decays “anti” phase space
29

           Novel states in

• J^P=0+,1-… 2632
     Narrow. Anomalous decays “anti” phase space
      cs* 1- radial (nodes); mix with ^3D_1


      cs*uu* (Iso violation);


      cqs*q* + css*s*(tetraquark in 15_f)
30
            Novel states in

• J^P=0+,1-… 2632
     Narrow. Anomalous decays “anti” phase space
       cs* 1- radial (nodes); mix with ^3D_1
       doesn’t work

       cs*uu* (Iso violation);
       D_s + pi^o     D_s + gamma gamma = NO

       cqs*q* + css*s*(tetraquark in 15_f)
       6_f more attractive; D_s gamma gamma = NO
31
     2632 would be here
32



     D_{sJ} summary


           2317/2460: cs* 0+ 1+ seeds
          Meson-meson S-wave DK D*K
             Dynamics like 0++(980)

                 2632: artefact
     Some Reflections on Pentaquarks




33
     ½+ Strangeness +1 baryon mass 1540MeV narrow width


               Predicted!!!   DPP

       In chiral soliton model with unusual assumptions


Narrow width an enigma
Mass a problem
Production mechanism unknown



         n.b. expt has not established ½+
         It might not exist!


34
 Jaffe Wilczek
                   Pentaquarks
     L=1
ud
ud          ud     (if they exist)
                   = strong QCD
                   correlations
      Q*


                  Diquark attractions
                  for unlike flavours =
ud L=1     udQ*   basis for pentaquark
                  models
                  (has not been demonstrated how
                  low mass scalar diquarks form,
                  stability, effective bosons,
Karliner Lipkin   consistency with other hadron
                  spectroscopy… etc. = ?)
Arndt
Buccella
Carlson
Dyakanov
Ellis
Faber
Giannini
Huang
Inoue
Jaffe       If Theta doesn’t exist,
Karliner
Lipkin
            then these (and many other theorists)
Maltman     should be congratulated on their creativity
Nussinov
Oh
Polyakov
Qiang
Rosner
Stech
Trilling
U
Veneziano
Wilczek
Xiang
Yang
Zhu
     Mass




37
                          + Baryon




   DPP original
   M=(1890-180Y)MeV                        and revised

Linear only for 10*. Mixing with 8 complicates.
Mass formulae beware |S| versus S. Strange quark costs too much
No simple map onto pentaquark
     Anomalies with Theta Mass?
          (LEPS)


                                              
                                        nK



           0
        pK S




39     F. Close and Q. Zhao, hep-ph/0404075
Mass                   Fitted. Not calculated


Dyakanov Petrov Polyakov DPP   assumed N(1710) in 10bar
X mass formula bizarre: q_5 10bar mass gap 1/3 m_s
X pure 10bar not photoproduced from p

Jaffe Wilzcek JW     assumed N(1440) as (ud)(ud)dbar
X width 300MeV
X gamma n:gamma p               = radial 56plet qqq
X Delta(1670) partner

Karliner Lipkin KL   assume cs* 200MeV orbital to set scale
X spin averaged cs* costs 500MeV, Theta= 1800MeV
      Jaffe Wilczek
                            What if……..?

     ud
     ud          ud    Q* \to (ud) = anomalous deuteron

                        Forces ud very light and L large
           Q*           What mechanism?




     ud         udQ*      (ud) \to Q* 10bar mesons
                           P-wave 1-+ etc? e.g.Chung Klempt
                           Widths? FC Dudek Burns
     Karliner Lipkin
41
     Width




42
                 Chiral Soliton Theta-N-K Coupling involves three
 Width           unknowns         A;    B;    C


                                               B         F/D
                 Set scale with                g(10*) = 1-B-C

                NRCQM: F/D=2/3        B=1/5
                                      C= 4/5
                                                           g(10*)=0




After
                             g(10*)
Ellis Karliner Prasalowicz




                                               C
     Width                   < 10 MeV direct experiments
                             <1MeV Cahn Trilling; Nussinov;…
     3/2- Lambda(1520) KN width 7 MeV
     X D wave; P-wave Lambda1600 is 100 MeV
     X needs qq* creation whereas qqqqq* falls apart


     Jaffe Wilzcek; Jennings Maltman; Carlson et al; Close Dudek;Buccella Stora
     Color flavor spin overlap suppression > 24
     X color killed by soft gluon exchange
     X spin flip costs little
     X flavor killed by rearrangement

     Stech et al; Dudek; Carlson et al
     Spatial overlap suppression
     X no dynamical proof Stech
     ? Strong color-spin forces (Dudek) + Stech model….?
44
 Width          < 10 MeV experiments
                <1MeV Cahn Trilling; Nussinov;…



     Decouples from KN (small width)

     Strong coupling to something (strong
     production)

          How is Theta produced?

     ………………enigma


45
     Production




46
     Several experimental limits in hadron production

Some not restrictive yet e.g. psi(3095) to Theta Thetabar
(=3080) versus LambdaLambdabar (1/100)
or can be “explained away” e.g. psiprime sees some
channels reduced and this is another one; big price to produce
10 q and q* etc.


My opinion (this week)
Limits in high statistics look impressive.
Onus is on supporters to explain them away or find a loophole



     ……….example of a possible loophole Lipkin Karliner   next
47
Why seen in photons but not in high statistics hadrons?

   CLAS: Theta+K = N*(2.4GeV)     (24ev/10bgnd)

    Suppose N*(uddss*) and gamma provides the ss*


  Problems       gamma
                            pi
                                        K
  CLAS see in          pi
                   N                    Theta
                             N*


  No memory of gamma(ss*);
  should apply to hadrons too…..why not CDF?

  SPring8 and CLAS1 too low E(gamma) to make 2.4GeV N*
     The Mystery of the Sigma_5

 • The case of the dog that didn’t bark
   (Sherlock Holmes)


     If Theta is real, why isnt Sigma_5
     (or Sigma* ½+ 1660) also seen?



49
     Decays    Dyakanov Petrov Polyakov; Close Dudek; Oh Kim Lee




              Note pKs can be + or +




         generalises


50
   Gamma N \to K Theta
Assuming s,t,u and contact diagrams
Gamma N \to K Sigma5




                       FC-Q Zhao
0.5




53
            Absence of Sigma_5, or even
                    Sigma(1660)
HERMES   in experiments that claim Theta is a
                       worry.




          R*(1520) ~ 1.6 ~ 3.5


M(pKs)
     Fake Peaks in gamma N     Dzierba Szczepaniak Teige


                  N



      N                  a2/rho3




          gamma




55
Fake Peaks in gamma N




 N                    a2/rho3       D/F wave decay
                                    forward back
                                    to KKbar

                                    a2/rho3
  N                                 gives charge asymmetry

  K                         K



Same velocity NK mass 1440
“real” kinematics broadens hump….   Dzierba Szczepaniak Teige
One is real (CLAS)
Three are fake

Can you tell which?
                      Dzierba Szczepaniak Teige
Could this also explain different nK+ and pKs masses?

                  (LEPS)                    Different Q values
                                            for charged neutral
                                           feed into mass of
                                 nK         fake Theta?




        0
     pK S

                                            Show Dalitz
                                            plots!!
     F. Close and Q. Zhao, hep-ph/0404075
     Paradoxes; Enigmas; Hints of unreality
       Cascades (exotics) studied since BQM Beware!
     Why does mass vary?
     real (dynamic clue); statistics (non existence clue)
     Decouples from KN (small width)
     Strong coupling to something (strong production)
     How is Theta produced?
     Why seen in low statistics photoproduction but
     not in high statistics hadroproduction?

 K-Theta+ why no K+Sigma-                  Why is production
 Ks Theta+ why no Ks Sigma+                Theta/Sigma(1660)
                                           = infinity?

59
               CONCLUSION
Have Weird Multiquark Demons been found?


     Is there a 1 MeV wide, S=+1 baryon at 1540 MeV?


If NO this is testament to the ingenuity of theorists whose
models can explain it even if it doesn’t exist.


Lattice QCD is almost unique in not having
definitively disproved that such a state does not exist.
                  CONCLUSION
  Precision and variety = Beyond qq*

  Strong Glue in QCD:
  Glueballs mix; psi to gam gam V opportunity.
  exotic hybrids emerging; Xi_{c1} decays opportunity

  Multiquarks/Molecules:
  X(3872) 1++ molecule (to be disproved)
Ds(2317;2460) 0+ and 1+: cs* or DK/DK* (need to determine)
Ds(2635) artefact (to be disproved)

  Pentaquarks/Theta:
  Artefact or Strong QCD very profound
  Opportunity for lattice to realise its investment
                     CONCLUSION
    Have Weird Multiquark Demons
    been found?

    Democratic voting paper/Florida counting principle


• YES

• No

•   Keep searching
With thanks to the organisers,

the scientific secretaries

and the IHEP students who have made
our time in Beijing so enjoyable
   This slide sponsored by Oxford
           University Press
• A Very Short Introduction to Particle Physics

A little red pocket book with no equations

for physics undergraduates and your partners

by
Frank Close

• 10 dollars at amazon.com now
Central Production pp \to pMp 0+ and 2+
              qq*           G?




         Compare e+e- \to e+(qq*)e-
        B decay = a new source of charmonium

A new narrow charmonium state

Charmonium problems




Standard cc* theory wrong?
Or is X(3872) not simple cc*?
   A conjecture: T.Barnes, F.E.Close, H.J.Lipkin, hep-ph/0305025, PRD.




Reminiscent of Weinstein and Isgur’s KKbar molecules,
bound by level repulsion of the KKbar continuum against
higher mass qqbar 0+ scalars at ca. 1.3 GeV.
Mass
       Low
       “N”(940) + “K”(495)       (L=1) = 115MeV

       (ud)+(uds*) < “N+K”
              (L=1) = 200MeV    Karliner Lipkin    Ds(cs*) spectrum
                                                             2.59
                                                             2.56




                                                  0+
                                                             2.32

                               210
                                                  1-
                                                             2.11

                                                             1.97
  Mass
            Low
            “N”(940) + “K”(495)         (L=1) = 115MeV

            (ud)+(uds*) < “N+K”
                   (L=1) = 200MeV   Karliner Lipkin
                                                       2+
                                                       1+
                                  L=1                       2.55 -
                                                            2.47

                                                      0+
Spin averaged masses in multiplet       400-480


                                                      1-
                                  L=0                       2.07
Theta = 1750-1830
                                                       0-
     Unique Isospin laboratory

I=3/2 and I=1/2
but for narrow states flavour wins:




   =(dss)dd*
                       10MeV
   =(dss)uu*
                MΘ

  (LEPS)


                              
                         nK

                         nK   pK S
                                   0




    0
 pK S




F. Close and Q. Zhao, hep-ph/0404075

				
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