SLAC 06/12/03 EPAC meeting Marcello A. Giorgi1 BABAR Status and Outlook Marcello A. Giorgi on behalf of BaBar Collaboration EPAC meeting - SLAC

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi2 BABAR DCH EMC DIRC COIL IFR SVT The B A B AR Collaboration 10 Countries 75 Institutions 579 Physicists Canada China France Germany Italy The Netherlands Norway Russia United Kingdom USA [4/18] [1/5] [5/55] [3/30] [11/101] [1/2] [1/3] [1/9] [10/66] [38/290]

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi3 New environment: high luminosity asymmetric collider 1)Search for CP violation in B meson decays largely predicted by the Standard Model 2)Test extensively at this low energy scale the Standard Model by measuring precisely enough quantities to impose constraints on the Standard Model parameters CP in b sector has been established by BaBar and Belle TRY to open windows on new Physics beyond Standard Model More precise CKM measurements, Rare B decays, Charm study, Tau rare decays. BaBar Physics GOALS

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi4 CP in Standard Model CKM quark mixing matrix b  ul B  (  ) l CP Violating phase B  D (*) l b  cl B  (  )  B 0 Mixing Unitarity

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi5 Experimental ingredients: BaBar optimized for time dependent CP asymmetries z   (4S) = 0.55 Coherent BB pair B0B0 B0B0   Start the Clock zz Tag vertex reconstruction Flavor Tagging Exclusive B Meson and Vertex Reconstruction     J/ 

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi6 Time dependent rate,flavor mixing and CP,T,CPT Time dependent rate: dN  exp(–|  t|/  B ) ( 1 ± D (S sin(  m  t) - Ccos(  m  t)) )  R CPV in Mixing -Decay CPV direct D is the mis-tag dilution R is the time resolution CP mixing decay z  0 CP & CPT violation CP and T Violation in mixing SM

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi7 Fit without the “usual assumptions”! Fit B  CP and B 0  flavor eigenstates (  / , q/p, z and CP left FREE) 90% C.L. The “usual assumptions” work!  Direct limit on   Test of CPT invariance  Indirect CP in mixing Preliminary

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi8 LOOK for N.P. in Loops? from charmonium channels Results are so far CKM compatible but… sssdsssd KSKS sssdsssd sin(2  ) = ± stat ± syst ?

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi9 B 0   +  -    sin2  eff With incomplete information on Penguin contamination: Measure S  and C  from both sin  m  t and cos  m  t terms. Compare with predicted S  and C  values for given , , |P/T|, and . Assume for instance: From sin2  eff to sin2  ? isospin analysis, needs B 0     cf. Gronau and Rosner, Phys. Rev. D65, (2002) BABAR Belle 1 Belle 2

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi10 B 0        )  the CP fit Time integrated direct CP: Time dependent CP: Asymmetry between rates: First step towards  in B  . Full Dalitz analysis in progress. Preliminary

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi11 Toward  : the B   D 0 CP K  approach sin2  from the triangles (Gronau-Wyler method): BaBar measurements: Preliminary

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi12 |V ub | from fully tagged SL decays Brecoil Breco D(*)D(*)  Y(4S) l XuXu Recoil of fully reconstruted B (~4KB /fb -1 ) b  ul signal: M X (< M D ) (  ~ 60-80%) S/B  1.7: good! Preliminary

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi13 Rare B decays b  u : tree, CKM suppressed b  s,d: Radiative (QCD, EM, EW) Penguins FCNC Leptonic decays: B 0  l + l -, B  , B  l +, … tree QCD penguin EM penguin EW penguin  probes b inside B Possible New Physics signatures: rates and phases from virtual particles in the loops

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi14 Not only B Physics in BABAR ! A new state decaying into D + s (1970) and  0 has been discovered by us and recently confirmed by CLEO! D + s  0 D + s  K + K -  + D + s  K + K -  +  0

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi15 An example: D mixing Very small in the S.M.  2  additional suppression  A window for new physics Charm, tau discovery potential lepton number is violated in many extensions of the S.M. (present limits, O (10 -6 ) are not far from some model predictions ) D0D0 c c u u d,s W-W- W+W+ V cd,cs V * cd,cs V * ud,us V ud,us D0D0 “long distance”  -iy “short distance”  x D0D0 D0D0 K-,K-, K+,+K+,+ Another example: lepton flavour violation S.M., extended to include mixing and mass:    BR(    O ( )

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi16 Luminosity: Present and Future FY2002 FY2003 Longer term So far in Run 3: On peak fb -1 Off peak 2.57 fb -1 By the end of the decade: 1  2 ab -1 Summer 2002 and Winter 2003: Run 1 + Run 2 On peak 83.9 fb -1 Off peak 9.6 fb M BB pairs Summer 2003: Run 3 add 40 fb -1 By end 2006: 500 fb -1

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi17 Next about sin2  Extrapolated statistical and systematic uncertainties Statistical uncertainty Golden modes (*) (*) This syst error of is dominated by DCS decays of charm in K tagged events. Lepton tag is not affected !

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi18 What next for Sin 2  Pure penguin process B  K s The present value with 80 /fb is: S=sin2  = stat.±0.09syst. With 2/ab  (S) goes down to 0.1 But also B  ’ K and B K K K NEW PHYSICS ? New quanta in the loop?

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi19 Results (0.08 ab -1 ) for BFactories Extapolations for sin2  eff Extrapolated errors (BaBar)

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi20 r=0.2 (2ab -1 ), sin 2  fit: sin 2    from B -  D 0 (CP) K - : projections Recent experimental results (BaBar) Toy MC projections: (Fit unreliable for r = 0.1) r=0.3 (0.5 ab -1 ), sin 2  fit  sin 2   A CP =0.174  r=0.2  =60 o  =30 o (2ab -1 )

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi21 projected errors for |V ub | Selection: One B reconstructed in D ( * ) X Lepton momentum and neutrino mass Kaon veto, charge balance Fit M x with constraints M X distribution fit: b  ul, b  cl, background Errors: Statistical L(ab -1 ) =  stat (%) = Experim. Systematic ~5% (now)  2.5% (b  cl bkgd) Theoretical ~ 9% (  (m b )=90MeV)  5% ( b  ul  above cut) M x (GeV)

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi22 B beam method “B – beam” Breco D(*)D(*)  Y(4S) l h B factories present an unique peculiarity. Events are pure B B and a full reconstruction of one side allow to treat the other as a pseudo B-beam. The study of rare decays with neutrinos are becoming possible with very high integrated luminosity.

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi23 Integrated luminosity vs physics BaBar2006  2009 ? 2002 Continuous improvement

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi24 Some comments about comparison with Hadron machine expts. CKM parametersBABAR/Belle BTeV/LHC-B 2 ab s Sin  (charmonium) 0.015stat/0.018syst 0.025/0.014 Sin  (penguins b  sss) 0.10 stat ---- in  S  eff (B 0  0.06 stat 0.024/0.056  eff –  ( B 0     ) <10° ---- Sin(  ) (B 0  D*     )  (B  DK) 7° <10°/<19° |Vub| 1.4%+ Th. Unc.(now better 10%) ---- Of course Bs mixing and decay can be studied well at hadron machines (  and a lot of good physics from Bs)

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi25 Rare decays - Summary ChannelBF BTeV/LHC-B (10 7 s) BABAR/BELLE (2 ab -1 ) b  s  3.3± K 6.8K(Btagged) B  K*  K24.0K B   (  )  K b  s  ± K 1.2K b  se+e- 1.4K B  K*  ± K/4.5K 0.5K B  K*e+e- 0.6K b  s ± BK* B   B   35  Limit< Bfactory and hadron machine measurements are complementary ! Rates… Fully reconstructed B on the other side are used The so called B beam option Asymmetries!

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi26 What about Detector? SVT! BABAR is a VERY good detector: very difficult to improve it!! (On IFR barrel is the only major intervention needed) SVT is 98% efficient. No degradation due to irradiation has been observed so far SVT so far tested for rad hardness up to 4 Mrad (OK!) rad tests are going on. Partial SVT replacement is considered by Almost 50% of modules built as spare.

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi27 Instrumented Flux Return –2000 m2 –342 barrel RPCs –432 endcap RPCs –32 cylindrical RPCs Electronics –3300 Front end cards ~ 40 mV threshold 16 channels connected to alternate strips Gas –35% Freon 134a, 4.5% iso-butane, 60.5% Argon –1-3 volume changes/day High Voltage –> kV HV pods

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi28 BABAR RPC Operates in limited streamer mode Parallel high resistivity plates (Bakelite   cm ) Graphite ~100 k  /  RPCs were filled 3 times with a mixture of 70% linseed oil and 30% n-pentane and dried by air for several days. Changes from L3 RPCs –Polycarbonate buttons with lip replaced G10 cylindrical button –Thicker oil layer –Single layer with strips on both sides –No mechanical envelope –Nonflammable gas - low iso- butane %, CBrF 3 replaced by Freon 134a C 2 H 2 F 4 Efficiency of barrel RPCs after production ~97%

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi IFR complete May 99 RPC efficiencies good Warning signs –Some RPCs with > 100 mA were disconnected With collision data –HV current limitations force reduction in # of RPCs Average Efficiency low ~85% Barrel is about 50% of total IFR coverage Forward Endcap about 40% Decision was taken in 2000 to upgrade the Forward Endcap with new RPC (higher QA/QC level) and with more absorber.

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi30 Absorber Segmentation 7 layers 2 cm 1 layer 7 cm 2 layers 9 cm 2 layers 13 cm 2 layers 10cm total 85 cm New Forward EndCap from nov 2002 Terminology: 19 slots and 15 RPC layers RPC belt Slot18/19 5 brass layers (slot 8,10,12,14,16)

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi31 RPC problems (post mortem photo) Gas inlet Debris Whiskers Excess oil Opposite side Linseed oil – uncured oils move under HV and warm temperatures Graphite layer develops high resistance Internal debris and whiskers 5% of barrel has HV problems before New HV distribution ~50% of the barrel modules leak (many have normal efficiency) Front End electronics problems

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi32 IFR Barrel Upgrade Muon selectors losing efficiency A committee was setup in september 2002 to evaluate physics motivation for a IFR upgrade and technology. B.Ratcliff and C.Hearty were chairing the committee. After 3 months the committee Presented its recommendations to BaBar. Many RPCs die since Fraction effectively dead is now almost 40%

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi33 Committee proposes to increase the thickness of the absorber and to replace the bakelite RPC with a more robust detector (Limited StreamerTube). INSTALLATION in 2004 & 2005 We have submitted a proposal and ask for your approval. FINAL DOCUMENT May22,2003

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi34 Summary Babar apparatus is generally very robust and can cope with high luminosity environment above Decision has been taken to upgrade the IFR Barrel with a different technology well established and robust (LST). Preliminary measurements of pure penguin processes for sin2 , measurements of Vub, B->DK, B->  including  Dalitz plot analysis. FUTURE – In 2005 complete the installation of the IFR Barrel. Install the Spare modules of SVT, to replace the heavily irradiated modules on horizontal plane. Approach the precision measurement with 0.5/ab of integrated luminosity. Towards more than 1.0/ab explore possible openings for new physics. Study of CP asymmetries but also rare decays in b, c and tau sectors. Profit from full reconstruction of one B : “ Pseudo B beam”

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi35 BACKUP SLIDES

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi36 Flavour mixing and CP,T,CPT  m=m H -m L  2|M 12 |  0.5ps -1 1/  1.6 ps  =  H -  L  |M 12 |Re (  12 /M 12 )  SM CP and T Violation in mixing As in K sector where  k =(p-q)/(p+q)  ~O(10 -3 ) SM

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi37 Flavour mixing and CP,T,CPT CP an CPT conservation if H 11 =H 22 CP and CPT VIOLATION Assumptions made in the usual sin2  analysis:

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi38 Time Dependent CP asymmetries CP eigenvalue Amplitude ratio B 0 f cp /B 0 f cp B mixing Measured from data (Flavour sample)! D mis-tag dilution R time resolution CPV in mixing-decay interference direct CPV dN  exp(–|  t|/  B ) ( 1 ± D (S sin(  m  t) - C cos(  m  t)) )  R Flavour tag

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi39 Search for B +  + B  candidate Semileptonic tag D0D0  Y(4S) cos  B,Dl  for B  D 0  X tags  Total signal-side neutral energy Semileptonic tags : BF(B +  + ) < 4.9  (90% CL) Fully reco tags: BF(B +  + ) < 7.7  (90% CL) combined : < 4.1  Preliminary

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi40 RPC efficiency % /month -0.56%/month Gas change

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi41 Detector studies Realization that the RPC efficiencies did not recover after cooling spurred detector studies –Efficiency was computed as a function of position Limited tests were carried out during accesses or on a few chambers –Lowered barrel temp. to 17  C. –Reversed HV –Increased gas flow –Lowered discriminator threshold –Put weights over inefficient regions No effect Gas composition was regularly tested –No evidence of water vapor A wide spread of plateau curves were measured.

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi42 RPC radiography The RPC efficiency was mapped in 2D showing irregular regions of reduced efficiency. D. Piccolo

SLAC 06/12/03 EPAC meeting Marcello A. Giorgi43 Occupancy plots for run Brick shields ~.8 m from L 16