BaBar Overview & Plans
Hassan Jawahery, spokesperson University of Maryland
SLAC Program Review June 12, 2007
1#
Outline Status of the BaBar Detector & Data collection and processing Status of the Collaboration BaBar physics impact and goals
Fresh results and more in dept coverage in Jim Olsen’s talk
Planning for future: 2008 and Beyond
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The setup of the experiment:
Operating at the U(4s) resonance
Help from Quantum Mechanics: U(4S)B0B0 with C=-1; The system remains entangled as it evolves. Critical for determining flavor of B0 when it decays in a CP eigenstate mode. B0-B0 Oscillation & inteference of mixing and decay allows extraction of time-dependent CP asymmetry.
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Major Activities of the Collaboration BaBar Upgrade:
Completed the upgrade of the Instrumented Flux Return (IFR)- replaced RPC’s with 12 layers of LST’s & 6 layers of brass in each of the remaining 4 sextants (2 sextants were done in 2004). Expect to fully recover muon and KL identification capabilities of the detector.
Startup of Run 6 in January 2007
Analysis of Runs 1-5 data set (390/fb) Planning for BaBar in 2008 & Beyond
Analysis and computing strategy State of the Detector after end of the data taking phase.
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5#
Muon ID capability fully restored with the upgraded IFR (better in fact)
LST
LST
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Timeline of Runs 6 & 7
Final work on cabling up and closing BaBar completed on January 6th;
Started collecting cosmic data with the magnet on within a few hours
1st stored beams in PEPII on January 15th and 1st data run on January 19th, as soon as the instantaneous luminosity reached ~1033 /cm2/s;
Run 6 will go on until September 3, 2007, to be followed by a 3month shutdown; The end date of Run 6 is determined by the planned work on LCLS. The nominal start up of Run 7 is December 4, 2007 to end on Sept. 30, 2008.
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Data taking in 2007
BaBar continues to collect most of PEPII delivery (dead-time typically at <2%)-crucial to keep thisImprovement in data-flow for SVT, DIRC, EMC are being implemented.
Enthusiastically awaiting the higher lumi’s from PEPII
A typical (good) day of BaBar running with PEPII
Running conditions tolerable thus far
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Data Processing:
Computing the BaBar data
Recently implemented major improvement to the tracking code; the processing of Runs 1-5 data nearly complete. – Expect significant benefit to the experiment in cleaner track lists & better measured tracks. The effects are even seen in Dt measurements.
Processing of the live data (Run 6) proceeding well and on target for use in analyses targeted for summer 07 conferences.
BaBar computing resources: Will require significant increment
in hardware and continued need for manpower resources to process and provide physics usable data to BaBarians. The magnitude of BaBar computing requirements is significantly straining the infrastructure at the lab. A source of worry for us, but we are working closely with a newly formed committee and SCCS to help and understand the plans.
Developing BaBar’s Analysis-Computing plans for 2008 & Beyond
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Completed a series of 3-workshops on assessing the need and benefit from a further reprocessing of the data in 2008 ; the decision built into the computing plans.
The BaBar Collaboration
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USA
California Institute of Technology UC, Irvine UC, Los Angeles U of Tennessee UC, Riverside U of Texas at Austin UC, San Diego U of Texas at Dallas UC, Santa Barbara U of Wisconsin UC, Santa Cruz Yale U of Cincinnati U of Colorado Colorado State Canada [4/23] Italy [12/90] Harvard U INFN, Bari University of British Columbia INFN, Ferrara U of Iowa McGill University Lab. Nazionali di Frascati dell' INFN Iowa State U University de Montréal INFN, Genova & Univ Johns Hopkins U University of Victoria INFN, Milano & Univ LBNL INFN, Napoli & Univ LLNL INFN, Padova & Univ France [5/40] U of Louisville INFN, Pisa & Univ & Scuola LAPP, Annecy U of Maryland Normale Superiore LAL Orsay U of Massachusetts, Amherst LPNHE des Universités Paris VI et VII INFN, Perugia & Univ MIT INFN, Roma & Univ "La Ecole Polytechnique, Laboratoire Sapienza" U of Mississippi Leprince-Ringuet INFN, Torino & Univ SUNY, Albany CEA, DAPNIA, CE-Saclay INFN, Trieste & Univ U of Notre Dame Ohio State U Germany [6/31] The Netherlands U of Oregon Ruhr Universitaet Bochum Princeton U Universitaet Dortmund [1/3] SLAC Technische Univeritaet Dresden NIKHEF, Amsterdam U of South Carolina Universitaet Heidelberg Stanford U Universitaet Rostock Norway [1/4] Universitaet Karlsruhe U of Bergen
[34/256]
10 Countries 77 Institutions 522 Physicists +21 non-Physicists
The BABAR Collaboration
Russia Spain
Budker Institute, Novosibirsk
[1/10] [2/7]
IFAE-Barcelona IFIC-Valencia
United Kingdom
U of Birmingham U of Bristol Brunel U U of Edinburgh U of Liverpool Imperial College Queen Mary , U of London U of London, Royal Holloway U of Manchester Rutherford Appleton Laboratory U of Warwick
[11/58]
October
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Status of the Collaboration
77 Institutions in 10 countries
Faculty
Canada France 10 13
PhD Staff
1 14
Postdoc
4 3
Grad
8 10
Non-PhD
4
Totals
23 44
Germany Italy
Netherlands Norway
7 29
1 2
5 30
3 11
16 20
2 2
1
32 90
3 4
Russia Spain
United Kingdom United States
2
21 79
7 2
2 54
1 2
16 50
1
2 13
11 7
60 269
3
19 73
Totals
164
115
89
154
21
543
The collaborations is on a very strong foundation
With 154 students and 89 postdocs, BaBar continues to be a major educational institution as well
One of the few remaining institutions for training future HEP physicists for the LHC & ILC 12# era
Manpower need to operate the experiment
BaBar’s technical coordinator (Bill Wisniewski) has determined that it takes ~ 110 of collaboration-FTE to operate (Detector maintenance and calibration, and computing tasks- excluding the technical and computing professionals) to operate BaBar. This also does not include the data taking shifts.
System managers have done detailed planning for coverage of the tasks till end of the data taking-e.g. for SVT:
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The evolution of service tasks & collaboration commitment
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BaBar Physics
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BaBar Data: Runs 1-5
BaBar collects ~97% of PEP II delivery
~ 0.4 x10 BB
9
Partial composition of the data 9
~ 0.5 x10 cc
~ 0.4 x10
9
& e e qq ISR
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The physics reach of the BaBar Data
Just about any physics that is accessible at
s 10 GeV
Origin of CP breaking
CP Studies with B’s & B Physics
CKM engineering
Search for NP
Charm Physics D0 Mixing; New States,FDs Lepton Flavor Violation Tau physics Continuum e+e- hadrons ISR: e+e- hadrons from threshold to ~5 GeV
New States –Y(4260)
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Some statistics on BaBar Physics
• There are more than 200 ongoing analyses of BaBar data.
• 284 published and submitted for publication so far
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A look at the timeline of our data collection vs our physics output
Probably a reflection of the fact that data is turned into physics in “real time” & more data is not just sqrt(N)- it also opens new thresholds for new channels
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The physics reach of the BaBar Data:charm Charm physics with ~ 0.4 x109 cc
Search for D0 mixing – highly suppressed in SM- a powerful window for NP searches Last summer Observables: from BaBar CP even state: width G1 , mass m1 ;
CP odd state: width G2 , mass m2 y = (G1 - G2) / (G1 G2) = DG / 2G x = (m1 – m2) / G = Dm / G
Last summer it appeared that the Limits were approaching the SM expectation
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Observation of D0 mixing
• Missing piece of the mixing puzzle
K 0 ( s d ) K 0 ( sd ) D 0 (cu ) D 0 (c u ) B 0 (b d ) B 0 (bd ) B 0 (b s ) B 0 (bs )
If no mixing
G(t) exp(-t) R + R y’ t + ¼ ( x’2 + y’2 ) t2
22#
The physics reach of the BaBar Data: B Decays
B Physics [with the ~ 0.4 x109 BB ] 109 BB
Investigation of CP violation in B meson Decays & tests of the CKM paradigm
Is the CP symmetry broken in B decays? Can we fit the CPV effects in the CKM picture?
Is there room for New Physics? Search for New Physics in rare (SM suppressed-FCNC) decays ? B Decays dynamics: Tests of QCD predictions
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Tests of the CKM Paradigm
Theorist view of CKM Observables The view from the experiments
g
a
Picture from A. Hoecker
Consistency of Indirect & direct constraints on apex of UT establishes the CKM as the primary mechanism for observed CPV effects in nature
sin 2 = 0.710 0.034( stat ) 0.019( syst )
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Prospects for the CKM observables with the “1/ab” data (~ +1/ab from Belle)
Aiming for: Now
~7%
Also counting on improved systematics in most areas & help from the theory side
( Vub |) 5% (g ) 5 10o (a ) 8o (sin 2 ) = 0.02
~20o ~11o ~0.04
& (Vtd/Vts)<4% (mostly from Tevatron).
25#
CPV in B decays: Direct CPV in Decay Amplitude
Within SM: Expect Acp(b->sg) ~ 0
Acp
Kp puzzle superweak is really out; to use as NP observable need reliable QCD predictions; Ample data to test & calibrate the calculations on.
26#
(B0Kp)= 0.099+/- 0.016
Another potential source of tension with SM
A major focus of the experiment is now on searches for New Physics via FCNC decays of B- Deviation from SM searched for:
gL bR
bL tL
There is more than just rate in these channels now:
d
W sL
•Photon polarization in bgsL (g left-handed in SM)
•Direct CP violation – nearly zero in SM •In BKll- q2 dependence of the rate; FB asymmetry, polariztion Search for NP modification of Wilson coefficients C7, C9, C10
W
Possible New Physics presence can alter the observables from SM expecations
b
u,c , t
g
s s s
d
Sin2 test in Penguin dominated modes
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Sin2 test in Penguin dominated modes
First “Observation” TDCP in a penguin dominated ,mode ~5.5 observations Accepted for PRL now
0.58 0.10 0.03 0.64 0.10 0.04
Simple average: Spenguins=0.52 +/- 0.05 vs reference point: sin2=0.68+/-0.03
~ 2.5 deviation at this point. Eagerly waiting for more data
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Planning for BaBar in 2008 & Beyond Analysis of the final data set
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The planning of BaBar in 2008 & Beyond
A detailed document has now been prepared and endorsed by the executive board of BaBar, and will be on its way to the International Finance Committee (July 07); The plan built on:
BaBar Physics Reach Assessment (R. Faccini et al BAD# 1228 in
2005)- Identified the list of “core” physics topics.
Report of the Beyond 2008 task force (C. Hearty et al, BAD# 1680, in 2006)
Endorsed the need for an Intense-Analysis Period (2009-2011) to perform the “core” measurements; Keeping all Tier-A centers active.
Conclusion of a series of workshops on potential benefits of full reprocessing (Run by Gregory & Jim Olsen.- Feb, March, May, 2007) Detailed study of computing resources needed to carry-out the program (Gregory DF& colleagues in computing) A study of the BaBar computing manpower needs & its time profile (Gregory, Mauro Morandin and Richard Mount)
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The planning of BaBar in 2008 & Beyond(cont’)
Guided by the need for timely performance of the key measurements that define the scientific mission of the program:
Precision knowledge of the Standard Model is an extremely important element of the search for “New Physics” in the (LHC) era, with the B factory data largely in charge of the flavor sector– “Textbook” measurements of the CKM sector are expected to emerge. Processes involving loop effects are expected to help in understanding the nature of the results that may emerge from LHC. To be relevant these measurements must be available on the same time scale. The key players in the analyses effort are the postdocs and graduate students, whose life span in the experiment is a major factor in defining the time window required for performing these measurements.
A period ~2-3 years of intense analysis activity, following the end of the data taking, in order to perform and publish the core physics channels.
Given the very broad physics reach of the “1/ab” data, the full exploitation of the physics will take much longer- LEP/SLC/CLEO experiences points to an overall 5-8 year program
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A list of topics on BaBar’s “core” physics program
The ultimate job on CKM – until the SuperB era
The no-stone-unturned search for New Physics
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The Analysis-Computing strategy for 2008 & beyond Develop & process Run 7 with the best reconstruction codethat can be tested and validated by mid- Fall 07:
Aim for presentation of preliminary results on most “core” physics channels at summer 2008 conferences. Plan for resources (hardware and manpower) for a full reprocessing of Runs 1-6 (or re-skimming).
Intense-Analysis Period 2009-2011:
The next major milestones for BaBar physics are winter and summer 2009 and 2010; commensurate with timescale of participation of current students and postdocs.
Required computing resources: Expect the need for the full resources and functionality of the distributed BaBar computing system, including the Tier-A and Tier-C centers.
The collaboration will continue to need a highly coordinated effort to best utilize its available manpower and resources. This will involve the continuing 33# presence of BaBar collaborators at SLAC, occupying most of the ROB space.
BaBar Analysis-Computing strategy for 2008 & beyond (cont’) Long term analysis of BaBar data:
• Guided by the experience of previous experiments at LEP & SLC, we expect that access to the full BaBar data set and a subset of the AWG skims on disk, as well as the ability to generate simulated data, will be required for a period of 3 to 5 years beyond the intense analysis period. In this era, we expect that a gradual shift will occur from the current distributed computing system to one in which SLAC serves as the central depository of the full data set as well as the AWG skims, and provides the CPU power required for data analysis. We also expect that the BaBar occupancy of the ROB will be reduced by about 1/3 to 1/2 each year, staring in about 2010.
Very long term access to BaBar data:
• Interest in the physics potential of BaBar data will likely continue well beyond the analysis phases outlined above. For this era, a model will need to be developed for archiving the data and maintaining its usefulness and accessibility to BaBar members and possibly nonBaBar members.
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State of the BaBar Detector Beyond the end of the Data taking phase
The collaboration has a strong desire and interest in keeping the detector fully intact, but in a minimum maintenance state, until at least the end of the intense-analysis period:
This would allow for performing further calibrations & tests, should the need arise from the examination of the data.
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The near-“1/ab” phase of BaBar is here:
Summary remarks
The LST installation, the last major detector upgrade, has successfully been completed & the muon Id capability of BaBar fully restored for the run 6 and run 7 data.
The collaboration is healthy with a strong base of students and postdocs.
An intense-analysis period of 2-3 yrs is expected to follow the end of the data taking period, requiring continued major support for the experiment.
An enormous amount of physics still to come from Flavor physics with BaBar in this phase. Two of the expected major outcomes are:
Precision knowledge of the charge weak sector of the SM & the CKM parameters; The CKM part of SM is still under construction (expt’s wise) With the possibility of revealing deviation from the SM
Measurements of CP violation and decay properties in rare decay modes, with the possibility of revealing New Physics effects. Hints are already present in the current data.
BaBar is continuing to serve as a major institution for educating future High Energy Physicists who will work on LHC and ILC. 36#
A brief history of major milestones in B physics
The 1/ab phase: Precision tests of the CKM paradigm- Search for N.P. using loop dominated B decays, LFV tau decays, DD(bar) mixing …
Precision sin2; a & g measured; CKM overconstrained and established as the primary source of observed CPV in nature. Data consistent with no NP effects in b-d and sd.
109--
108--
107--
#B’s 106--
2001- CPV in B decays observed. Sin2 consistent with SM
1999- B Factories start operation. 1993-Radiative penguin bsg observed; Major constraint on models of New Physics;Rare decays BKp and pp obserevd; Role of gluonic penguins established;
B factory projects launched.
105-1987-B0 mixing & Vub measured; Lower bound on m(top)>42 GeV; with non-zero Vub, CKM in the game as a source of CPV
104--
1982-B meson observed
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