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Exploring CP Violation in B Mesons: Insights from BaBar Collaboration

Discover the latest achievements and future mission of the BaBar Collaboration in the field of particle physics, focusing on CP violation in B mesons and precision measurements beyond the Standard Model. Learn about flavor mixing, CPT violation, and unitarity relations in the CKM matrix along with recent experimental findings in the B sector. Explore the journey towards unraveling new physics phenomena and the quest for high-precision measurements with innovative techniques.

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Exploring CP Violation in B Mesons: Insights from BaBar Collaboration

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  1. BABAR Future Marcello A. Giorgi at SLAC B DAY Marcello A. Giorgi

  2. Outline • BaBar Collaboration • BaBar Mission • Present Achievements • What Next....... Marcello A. Giorgi

  3. Italy [11/101] INFN, Bari&U INFN, Ferrara&U Lab. Nazionali di Frascati dell' INFN INFN, Genova&U INFN, Milano&U INFN, Napoli&U INFN, Padova&U INFN, Pisa&U&ScuolaNormaleSuperiore INFN, Roma &U "La Sapienza" INFN, Torino&U INFN, Trieste&U The Netherlands [1/2] NIKHEF, Amsterdam Norway [1/3] U of Bergen Russia [1/9] Budker Institute, Novosibirsk United Kingdom [10/66] 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 USA[38/285] California Institute of Technology UC, Irvine UC, Los Angeles UC, Riverside UC, San Diego UC, Santa Barbara UC, Santa Cruz U of Cincinnati U of Colorado Colorado State Florida A&M Harvard U of Iowa Iowa State U LBNL LLNL U of Louisville U of Maryland U of Massachusetts, Amherst MIT U of Mississippi Mount Holyoke College SUNY, Albany U of Notre Dame Ohio State U U of Oregon U of Pennsylvania Prairie View A&M U Princeton U SLAC U of South Carolina Stanford U U of Tennessee U of Texas at Albany U of Texas at Dallas Vanderbilt U of Wisconsin Yale The BABAR Collaboration 10 Countries 75 Institutions 569 Physicists Canada [4/18] U of British Columbia McGill U U de Montréal U of Victoria China [1/5] Inst. of High Energy Physics, Beijing France [5/52] LAPP, Annecy LAL Orsay LPNHE des Universités Paris VI et VII Ecole Polytechnique, Laboratoire Leprince-Ringuet CEA, DAPNIA, CE-Saclay Germany [3/28] Ruhr U Bochum Technische U Dresden U Rostock January 14, 2003 Marcello A. Giorgi

  4. Marcello A. Giorgi

  5. LUMINOSITY After a long run period July 1,2002 Babar & PEPII RUN 2 stopped. RUN 3 has started Nov.18,2002 and after the short wintershutdow (dec 23-jan 2) operation is continuing in 2003 RUN 1 & RUN 2 PEP has delivered 98.5 fb-1 BABAR recorded 83.9 fb-1 (on peak) 9.9 fb-1 (off peak) RUN 3 PEP has delivered 16.12 fb-1 BABAR recorded 15.49 fb-1 (on peak)1.16 fb-1 (off peak) B pair collected (Runs 1+2+3) 112 Million Marcello A. Giorgi

  6. At the end of the present Run 3 (June 29) we expect more than 40 fb-1 Jun 29 Marcello A. Giorgi

  7. BaBar Physics Mission New environment: high luminosity asymmetric collider 1)Search for CP violation in B mesons 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 is FOUND ! We move now toward the second part of our mission Precision measuremets B physics, rare B decays TRY to open windows on new Physics beyond Standard Model Marcello A. Giorgi

  8. Flavour mixing and CP,T,CPT = Let us remind the Effective Hamiltonian to describe system, where the mass eigenstates BH and BL are: and Marcello A. Giorgi

  9. Flavour mixing and CP,T,CPT Dm=mH-m L 2|M12|  0.5ps-1 1/G  1.6 ps DG=GH-GL  |M12|Re (G12/M12) DG<<G SM CP and T Violation in mixing As in K sector where ek=(p-q)/(p+q) e~O(10-3) SM Marcello A. Giorgi

  10. Flavour mixing and CP,T,CPT CP an CPT conservation if H11=H22 CP and CPT VIOLATION Marcello A. Giorgi

  11. mixing decay CP Flavour mixing and CP,T,CPT CPV in Mixing Decay CPV direct Time dependence: dN exp(–|Dt|/tB) ( 1 ± D (Ssin(DmDt)-Ccos(DmDt)) )  R D is the mis-tag dilution R is the time resolution Marcello A. Giorgi

  12. CP in the Standard Model CP is explained in S.M. by the presence of a phase among the 4 parameters of the flavour mixing matrix CKM In the above parametrization ,where lis sin qc , h is the parameter contributing to CP Marcello A. Giorgi

  13. Representing unitarity relations as Unitarity Triangles The unitarity condition of CKM matrix V V+=V+V=1 gives several relations between the matrix elements as VudV*ub + VcdV*cb + VtdV*tb =0 (in this relation the 3 terms have the same orderof magnitude~O(l3) and it can be graphically represented as a triangle in a complex plane with sides of comparable length. Other relations have terms of different order of magnitudes.Ex: VusV*ub + VcsV*cb + VtsV*tb =0 O(l2) O(l2) O(l4) Overconstrain a,b,g and the 4 parameters of CKM r,h, A,l Marcello A. Giorgi

  14. Measurement of sin2b=0.741 0.067 0.034 hcp=-1 hcp=+1 sin2b = 0.755  0.074 sin2b = 0.723  0.158 PRL 89(2002) 201802 Marcello A. Giorgi

  15. CP discovery in B sector Osaka -2002 Rome- 2001 Amsterdam- 2002 Marcello A. Giorgi

  16. CP,T,CPT A simultaneous fit to tagged and untagged data gives : Dm ,sin2b (consistent with previous analysis) |Acp/ Acp | (consistent with no direct CP violation (4.5%) 90% CL Marcello A. Giorgi

  17. CP,T,CPT From dileptons Marcello A. Giorgi

  18. What next for Sin 2b 0.5 ab-1 We can improve the expt. error on sin2b with luminosity in time dependent asimmetry for channels as: bccs O(l2) (golden as J/yKs) or bccd O(l3) (as D (*)+ D(*)-) , where the leading term gives sin2b 0.5 ab-1 Marcello A. Giorgi

  19. What next on sin2b F Measure sin2b also in FK (bsss pure penguin) K(*) B K± Ks 80 Million B pairs Marcello A. Giorgi

  20. Time dependent analysis Results: Assuming C=0 (no direct CPV) S=sin2b=-0.26±0.51 stat. On control sample Charged K expected S=0 Found S=0.26 ±0.27 stat. Marcello A. Giorgi

  21. Towards sin2eff: Spp and Cpp B0 → p+ p - BaBar (Br/10-6): B0p+p-=4.7±0.6 ± 0.2B p+p0=5.5 ± 1.0 ± 0.6B p0p0=<3.6 Marcello A. Giorgi

  22. 2d a from pp F In a full isospin analysis one can measure F and F’ from B and B decays with a 4-fold ambiguity F’’ Fix :BR(p+ p-)= 4.7x10-6,BR(p- p0 ) = 4.1x10-6 and assumingBR(p0 p0) 1.0 x10-6 L = 0.5 ab-1 L = 2.0 ab-1 fb-1 Marcello A. Giorgi

  23. Bound on d 2d sin2aeff = -0.02`0.34`0.05 with 2aeff = 2a + 2d Grossman-Quinn bound: F At present BR(B0→p0p0) < 3.610-6 (81 /fb) _d=|aeff-a| < 51o F’’ best case: |aeff – a | < 190 with 10 fb-1 No significant gain with luminosity Best case with this method signal BR = 0.5e-6 Marcello A. Giorgi

  24. Measuring g with B+D0 K Gronau,London and Wyler Take decayB± D01(D02)K ±whereD01,2=(D0±D0)/2 B+ decay amplitudes can be written as: and Marcello A. Giorgi

  25. Measuring g with B+D0 K+ actual detector: ai=0.177 “perfect” vertex detector: ai=0.133 (noBkg) Marcello A. Giorgi

  26. New results with full statistics To complete the measurements odd CP eigenstates are needed as Ks p0 and Cabibbo suppressed modes Marcello A. Giorgi

  27. g from B+D0 K+ Fit:sin2g = 0.720.23 => g = (59.910.2)o Toy MC: results for r=0.3 0.5 ab-1 Fit with 2ab-1 (perfect): sin2g = 0.710.14 (sin2g =0.730.09) =>g = (58.57.4)o (g = (58.85.5)o) input value (sin2g=0.75) sin2g input value (sin2Dd=0) Marcello A. Giorgi

  28. Measuring Vub We are after the red part and one want to go as close as the D mass Measure Br(buln) on the recoil of fully reconstructed B. Close kinematics: P*l, Q2 and Mx available Reco side Before lepton selection: >3K events/fb-1, S/B=0.5 After lepton selection: ~500 events/fb-1, S/B=1.3 Marcello A. Giorgi

  29. The theoretical error of 10% can be further reduced at the 5% level using all information P*l, Q2 and Mx Assuming a 5% theoretical error and a 5% experimental systematic error, here are the projections of the error as a function of the luminosity Current error N.B. this estimate neglects the fact that the full fledged theorethical extraction becomes feasible only with enough statistics Marcello A. Giorgi

  30. …and with higher and higher luminosity: Rare B decays, for instance: Loop-mediated, FCNC: b  sl+l-, b s , b  s Leptonic: B  , … Unique possibility at B factories: fully reconstructed B tag  0.1% efficiency, very useful for channels with missing energy () Just began to exploit this possibility Marcello A. Giorgi

  31. ...more.. Charm and Tau Physics Search for mixing and CP violation in D meson decays, … Rare  decays, including LFV Marcello A. Giorgi

  32. Integrated luminosity vs physics 2002 2006  2009 ? BaBar Physics examples: choose benchmarks Marcello A. Giorgi

  33. From task force on Long Term Upgrades Some Highlights: BABAR is a VERY good detector: very difficult to improve it!! (IFR is the only intervention needed) Only a few channels are systematically limited below 1 ab-1 ; many topics would benefit from 2-3 ab-1 or more We need to integrate higher luminosity, well beyond 0.5 ab-1, to better constrain the Unitarity triangle, to study rare decays and try to open windows on New Physics. More resources to PEPII would be beneficial for Physics Marcello A. Giorgi

  34. SVT has been un-cabled,taken to the clean room, split in two halves and removed from the B1 magnets • Once the SVT was exposed electrical tests and visual inspections were performed. We discovered the reason for some of the failures of the 9 non functioning readout sections,some modules fixed! Now only 4 out of 208 sections are not readable. SVT SVT so far tested for rad hardness up to 4 Mrad (OK!) rad tests are going on. Partial SVT replacement of modules already built,tested and soon ready in Pisa and UCSB is considered by 2005 Marcello A. Giorgi

  35. New Forward EndCap Terminology: 19 slots and 15 RPC layers RPC belt Slot18/19 5 brass layers (slot 8,10,12,14,16) Absorber Segmentation 7 layers 2 cm 1 layer 7 cm 2 layers 9 cm 2 layers 13 cm 2 layers 10cm total 85 cm Marcello A. Giorgi

  36. Decreasing efficiency Some RPC completely off Barrel IFR Upgrade The problem: dying RPCs. Muon selectors losing efficiency impacting physics Marcello A. Giorgi

  37. IFR Barrel Upgrade • Decision on technology made during Dec Collaboration Meeting. • Project based on LST will be ready (WBS) by end of may 2’’3 and will be reviewd in June. • Access for replacement of current RPCs is mechanically complex: significant engineering needed. Expect to upgrade in 2004 and 2005 to avoid an extremely long shutdown. Marcello A. Giorgi

  38. PEPII – “adiabatic” scenario 0.5 ab-1 1.6 x 1034 2006 Marcello A. Giorgi

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  40. Marcello A. Giorgi

  41. A very promising physics program • We have a and ambitious physics program until the end of this decade based on increase of of PEP II luminosity with a more aggressive scenario if the integrated luminosity would go well beyond 1/ab by the end of the decade. Marcello A. Giorgi

  42. What after 2010 In B physics beyond 1- 2/ab? A lot of measurements but.... ...........10 36?? Possibly yes! Marcello A. Giorgi

  43. BACKUP Marcello A. Giorgi

  44. Towards sin2: B0  Acp Marcello A. Giorgi

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