BABAR Status & Plans David B. MacFarlane SLAC EPAC Meeting January 25, 2006

Jan 25, 2006BABAR Status and Plans2 Pillars of BABAR physics program  Highly constrained and redundant set of precision tests of weak interactions in the Standard Model  Searches for physics beyond the Standard Model in a well understood & characterized environment oSensitivity to New Physics at LHC mass scales through rare decays and CP violation oDiscovery potential from large data sample across a whole range of beauty, charm, tau, two-photon, ISR physics oFull program of flavor physics/CP violation measurements will provide a legacy of fundamental constraints on future New Physics discoveries Challenging measurements at the edge of sensitivity benefit enormously from operation of both PEP-II & KEK B Factories

Jan 25, 2006BABAR Status and Plans3 The BABAR Collaboration 11 Countries 80 Institutions 623 Physicists

Jan 25, 2006BABAR Status and Plans4 BABAR & Belle physics results BABARBelle Journal Papers184155

Jan 25, 2006BABAR Status and Plans5 Integrated data sample to date 96% efficiency over the entire history of BABAR BABAR, Run 5

Jan 25, 2006BABAR Status and Plans6 ParameterUnitsDesignOct 2005 I+mA I-mA Number of bunches y*y*mm Bunch lengthmm yy Luminosityx Int lumi / daypb PEP-II overall parameters and goals More than 3x design More than 5x design

Jan 25, 2006BABAR Status and Plans7 ParameterUnitsDesignOct goal I+mA I-mA Number of bunches y*y*mm Bunch lengthmm yy Luminosityx Int lumi / daypb PEP-II overall parameters and goals 30%40% 10% Factor 2!

Jan 25, 2006BABAR Status and Plans8 Projected data sample growth Integrated Luminosity [fb -1 ] L peak = 9x10 33 oPEP-II: IR-2 vacuum, 2xrf stations, BPM work, feedback systems oBABAR: LST installation 4-month down for LCLS, PEP-II & BABAR Double from 2004 to 2006 ICHEP06 Double again from 2006 to 2008 ICHEP08

Jan 25, 2006BABAR Status and Plans9 IFR upgrade with LSTs Bottom & top sextants installed summer 2004 Remaining sextants delayed until fall 2006

Jan 25, 2006BABAR Status and Plans10 Weak Interaction in Standard Model Unitarity Triangle as a summary of Standard Model b physics + phases

Jan 25, 2006BABAR Status and Plans11 Classic indirect constraints 2008: ~5%

Jan 25, 2006BABAR Status and Plans12 Weak Interaction in Standard Model Unitarity Triangle as a summary of Standard Model b physics + phases CP violation CKM elements & quark masses are fundamental constants emerging from EW symmetry breaking

Jan 25, 2006BABAR Status and Plans13 Interference of b  c tree decay with mixing CPV in charmonium modes

Jan 25, 2006BABAR Status and Plans14 Interference of suppressed b  u tree decay with mixing CPV in charmless modes 3 rd component: sizable Penguin diagram

Jan 25, 2006BABAR Status and Plans15 Remarkably good progress on gamma! Interference of color-allowed and color-suppressed tree decays Effect depends on ratio of two diagrams

Jan 25, 2006BABAR Status and Plans16 Direct CP violation measurements 2008: ~2% 2008: 10 o 2008: 5-10 o

Jan 25, 2006BABAR Status and Plans17 UT from sin2  & indirect constraints Paradigm change! Now: looking for New Physics as correction to CKM Overconstrained: growing set of independent measurements are consistent with CKM picture

Jan 25, 2006BABAR Status and Plans18 UT from CP violation measurements alone New B Factory milestone: Comparable UT precision from CPV in B decays alone Overconstrained: subsets of measurements can be used to test for new physics

Jan 25, 2006BABAR Status and Plans19 Interference of suppressed b  s Penguin decay with mixing CPV in Penguin Modes Another implication of overconstrained: redundant approaches to same CKM parameter

Jan 25, 2006BABAR Status and Plans20 Potential New Physics contributions “Internal Penguin” SUSY contribution with new phases New physics in loops?

Jan 25, 2006BABAR Status and Plans21 Revealing new physics LHC B Factory Squark mass matrix (d sector)

Jan 25, 2006BABAR Status and Plans22 Summary after summer 2005 updates No sign of Direct CP 2.4  between CP violation in s-penguin vs sin2  (cc) Summer 05 results About 0.5  loss vs Winter 2005 due to shift in charmonium average Charmonium s-Penguins

Jan 25, 2006BABAR Status and Plans23 BABAR CKM physics goals PhysicsImpactFY fb -1 FY fb -1 FY fb -1 Precision measurement of sin2  Fundamental constant of the SM, whose precision is only limited by statistics Improve error by factor of two to 2% Precision measurement of CP asymmetry in penguin modes Primary approach to new physics in loop decays; presently discrepant with SM predictions at 2.4  level when averaged over all available modes Potentially reach the 4-5  level for average of all modes Could reach the 4-5  level for individual theoretically- clean modes Precision measurement of unitarity angle  Fundamental constraint on the UT Discovery of if it has SM branching fraction Isospin analysis in allows better than 10 o measurement Precision measurement of unitarity angle  Fundamental tree-level constraint on phases and amplitudes originating from any new physics beyond the SM Pioneering measurements with o accuracy Determine to 5-10 o precision Precision measurement of with inclusive & exclusive semileptonc B meson decays Fundamental tree-level constraint on amplitudes and phases originating from any new physics beyond the SM Inclusive decays reach 6.5% precision Exclusive decays reach 8% precision

Jan 25, 2006BABAR Status and Plans24 Global CKM fit: % contours

Jan 25, 2006BABAR Status and Plans25 Projections to summer 2008 K*K* 5  discovery region if non-SM physics is 0.30 effect 2004=240 fb =1.0 ab -1 Golden modes reach 5 sigma level Projections are statistical errors only; but systematic errors at few percent level Luminosity expectations : f 0 K S K S  0  K S  ’K S KKK S

Jan 25, 2006BABAR Status and Plans26 now 2008 UT constraints in 2008 Assumption: no NP in trees [almost any NP model] 95% contours Significant constraint on all New Physics models in LHC era

Jan 25, 2006BABAR Status and Plans27 Bounds on new physics in B d mixing now 2008 Model independent Mass scale being probed for unit coupling:  (now) ~ 5 TeV  (2008) ~ 10TeV Introduce new physics in mixing diagram

Jan 25, 2006BABAR Status and Plans28 BABAR rare decay physics goals PhysicsImpactFY fb -1 FY fb -1 FY fb -1 Discovery ofProvides a determination of and constrains Higgs sector in MSSM and NP in a parameter regime that is complementary to LHC LimitFirst hintsDiscovery if it has SM branching fraction Precision determination of branching fraction, CP asymmetry, and photon energy spectrum Loop diagram that provides unique insight into B meson structure and constrains Higgs sector in MSSM and NP in a parameter regime that is complementary to LHC Ultimate precision on photon energy spectrum Strong constraints from 5% error on BF; 1-2% error on CP asymmetry Precision determination of branching fractions, CP and FB asymmetries Contributions from Z-penguin and W-exchange loops that give additional constraints on MSSM and NP in a parameter regime that is complementary to LHC Useful precision for constraints on NP Strong constraint for NP from BF, CP and FB asymmetries Discovery ofProvides a unique determination of CKM matrix elements ; likely before mixing discovery First hintsDiscovery if it has SM branching fraction Precise measurement of BF

Jan 25, 2006BABAR Status and Plans29 New CKM constraints in sight W,H 2008: Possible discoveryPossible discovery: 2007

Jan 25, 2006BABAR Status and Plans30 Complementarity with LHC today 2008 Approx… 2HDM Constraints from B , B  s 

Jan 25, 2006BABAR Status and Plans31 BABAR Physics Goals PhysicsImpactFY fb -1 FY fb -1 FY fb -1 Search for mixingHighly suppressed in the SM and therefore an ideal place to search for new physics in charm mixing diagram Hint if 1% mixing amplitude Discovery if 1% mixing amplitude Search for lepton-flavor violation in or other tau decays Expected to be significantly enhanced in many extensions of the SM accommodating neutrino mass, but extremely small in the SM itself Limits reach 2x10 -8 sensitivity New discovery in heavy hadron spectroscopy Improved understanding of QCD in non-perturbative regime Discoveries possible anytime

Jan 25, 2006BABAR Status and Plans32 Lepton-flavor violation & mSUGRA tan  = 55 Inverted hierarchy s-  is LSP allowed Br(   e  ) < 1x x x x10 -8 Current BABAR limit 2008 limit

Jan 25, 2006BABAR Status and Plans33 Summary: Physics plans for BABAR  Goal for : double current data set o Delay in Run 5 can be overcome by summer 2006 with extended running period, with substantial reduction in errors on CP violation asymmetries in rare decay modes o Error on average of Penguin modes should reach 0.06  Goal for : double again to ~1 ab -1 o Individual Penguin modes with errors in range o Suite of fundamental Standard Model measurements with substantially improved levels of precision  Beyond 2008 might offer exciting opportunities if New Physics has been seen by B Factories & LHC oSensitivity to New Physics through rare decays, CP violation, & large data sample with a significant discovery potential oFull program of flavor physics/CP violation measurements provide fundamental constraints on future New Physics discoveries

Backup Slides

Jan 25, 2006BABAR Status and Plans35 A day in the life of a B Factory

Jan 25, 2006BABAR Status and Plans36 PEP-II performance: peak luminosity

Jan 25, 2006BABAR Status and Plans37 BABAR Detector DIRC  PID) 144 quartz bars PMs 1.5T solenoid EMC 6580 CsI(Tl) crystals Drift Chamber 40 layers Instrumented Flux Return Iron / Resistive Plate Chambers or Limited Streamer Tubes (muon / neutral hadrons) Silicon Vertex Tracker 5 layers, double sided strips e  (3.1GeV) e  (9GeV) Collaboration founded in 1993 Detector commissioned in 1999

Jan 25, 2006BABAR Status and Plans38 DCH electronics upgrade  Motivation: o Remove anticipated deadtime problem due to serialization and shipping of data from DCH to readout module  Upgrade in two steps: o Phase 1 (summer 2004): L1 to ~4kHz Reduce ADC payload (32  16 bytes) from front ends with no impact on dE/dx performance o Phase 2 (Oct 2005) : L1 to ~5kHz Larger FPGA to allow feature extraction on DCH endplate New boards installed in Oct down, ready to activate FPGA code

Jan 25, 2006BABAR Status and Plans39