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B-Factories: Physics Reach

B-Factories: Physics Reach. Luminosity CPV and CKM Rare B decays Conclusions. Livio Lanceri – Univ. and INFN Trieste INFN-CSNI – LNF, February 4, 2003. Discovery potential at the B factories. CKM and Unitarity Triangle SM predicts a pattern of CPV, from phase in the CKM matrix

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B-Factories: Physics Reach

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  1. B-Factories: Physics Reach Luminosity CPV and CKM Rare B decays Conclusions Livio Lanceri – Univ. and INFN Trieste INFN-CSNI – LNF, February 4, 2003

  2. Discovery potential at the B factories • CKM and Unitarity Triangle • SM predicts a pattern of CPV, from phase in the CKM matrix • B factories can measure both angles and sides of the Unitarity Triangle • New phases from New Physics may reshape the UT • Rare B Decays • CKM suppressed (tree b  u), Radiative Penguins (QCD, EM, EW), leptonic B decays • Common feature (Penguins, leptonic): New Physics signatures from rates and asymmetries (new virtual particles in the loops) • Charm, tau • Examples: D mixing and lepton number violating  decays • Very small in SM  windows for New Physics L.Lanceri - B-Factories: Physics Reach - CSNI

  3. Inclusive tag (lepton, K, …): tag(1-2w)2 28% (Exclusive tag: tag  0.10.2%) z(CP) z(tag) rec  1540% < z >  260 m z (RMS) 190 m Experimental ingredients Asymmetric B factories optimized for measurements of time-dependent CP violating asymmetries OK also for other measurements (rare B decays, …) Open trigger! No B physics losses at trigger level High efficiencies, small bkgd Unique tool at B factories: exclusive B tagging with fully rec. B (“single B beam”) Luminosity is a key factor L.Lanceri - B-Factories: Physics Reach - CSNI

  4. BABAR/PEP-II Record peak luminosity: 4.6 x 1033cm-2s-1(~5 BB/s) max lumi/24h: 303 pb-1 total recorded lumi to date: ~0.1 ab-1 (~10% off-peak) Restarted end Nov.2002 after 4 months shutdown (Forward IFR upgrade) Belle/KEK-B Record peak luminosity: 8.2 x 1033cm-2s-1(~8 BB/s) max lumi/24h: 433 pb-1 total recorded lumi to date: ~0.1 ab-1 (~10% off-peak) Restarted in January 2003 after vacuum loss forced stop in December B-Factories: experiments and luminosity • c.f. integrated luminosity for • Argus (1983-1987): ~100 pb-1 • CLEO (1981-2000): ~16 fb-1 L.Lanceri - B-Factories: Physics Reach - CSNI

  5. PEP-II without upgrades 1.1 ab-1 1.6 x 1034 peak integrated 0.5 ab-1 2006 2009 L.Lanceri - B-Factories: Physics Reach - CSNI

  6. NO (Super-KEKB?) Minimal upgrade Feasible from 2005 Shut-down  3 months 0.40.5 ab-1/year Limited cost SuperPEP/SuperBaBar Year 20...? New collider, (and new detector…) Snowmass: 370M$ 2ab-1 in 2009 PEP-II upgrade scenarios From J.Seeman/SLAC L.Lanceri - B-Factories: Physics Reach - CSNI

  7. Path to higher PEP-II luminosity Luminosity4.6E331E342E344E34Units I+ 1800 2700 3600 4500 mA I- 950 1400 1760 2000 mA Beta y* 11.5 9 7 4.5 mm Beta x* 50 50 50 50 cm Bunch Length 1.3 1.0 0.8 0.5 cm # bunches 792 1300 1500 1600 Vert. Emitt. 2.5 1.4 1.1 0.7 nm Horiz. Emittance 40/50 30/45 32/47 40/48 nm (+/-) Crossing angle 0 0 0 ~+/-8 mrad Tune shifts (x/y) 7.5/4.5 8.0/5.7 8.2/6.0 8.4/6.3 x100 Number RF stations 7 10 13 15 Date hardware ready Jan 02 Dec 02 Dec 04 Nov 05 Date for luminosity Jun 02 July 03 Dec 05 Dec 06 (J.Seeman, BaBar Collaboration meeting, Sept.2002) L.Lanceri - B-Factories: Physics Reach - CSNI

  8. BaBar Long Term Planning TF For the 4x1034 PEP-II upgrade: We studied the physics reach in some channels for: 0.5 ab-1 (2006), 2.0 ab-1 (end of the decade) And: Interest/need of an accompanying BaBar detector upgrade ? (Conclusion: only Barrel IFR) Most extrapolations reported here come from the preliminary report of the TF L.Lanceri - B-Factories: Physics Reach - CSNI

  9. What about KEK-B/Belle upgrades ? EoI (January 2002): Super KEK-B, L = 1035cm-2s-1 - LER: e- , I = 10A; HER: e+, I = 3A Linac upgrade (e-  e+) - Vacuum system (ante chambers); RF system (52 cavities, 12SC) - 15 mrad crossing, final focussing Total cost (KEK-B + Belle):  400 M$ EoI preliminary plan: Present plans: … ?? Workshop at KEK, Feb.2003 L.Lanceri - B-Factories: Physics Reach - CSNI

  10. CPV and CKM: phases sin2 sin2 

  11. CP eigenvalue Amplitude ratio B0fcp/B0fcp B mixing CP asymmetry: Time Dependence CPV in mixing-decay interference direct CPV dN exp(–|Dt|/tB) ( 1 ± D (Ssin(DmDt)-Ccos(DmDt)) )  R Flavour tag D mis-tag dilution R time resolution Measured from data (Flavour sample)! L.Lanceri - B-Factories: Physics Reach - CSNI

  12. BaBar, sin2b: results Charmonium modes on-peak: 81.9 fb-1 off-peak: 9.6 fb-1  89 M BB pairs sin2b = 0.755  0.074 sin2b = 0.723  0.158 sin2b = 0.741  0.067  0.034 tagged CP sample: 2631 flavor sample: 25375 Modes with Penguins Yield (pure Penguin!) in Standard Model L.Lanceri - B-Factories: Physics Reach - CSNI

  13. decays with charmonium: Source dsin2b CP and Mix BG DCS decays, tag side 0.017 0.008 Klong BG 0.015 Dt meas. and RF 0.017 Signal Dilutions 0.012 Fit bias correction 0.010 B lifetime 0.004 Dmd 0.003 Total 0.034 BaBar, sin2b: systematics Asymptotic 0.004 0.008 0.003 0.010 0.010 0.003 0.003 0.003 0.018 Using only lepton tags: 0.01 L.Lanceri - B-Factories: Physics Reach - CSNI

  14. sin2b: projected errors (BaBar) • Extrapolated statistical and systematic uncertainties Statistical uncertainty For “golden” modes only L.Lanceri - B-Factories: Physics Reach - CSNI

  15. u b t d p- p- u d B0 B0 b u u p+ d d p+ d d Mixing + T: b+g P: -b,d sin2eff fromB0+- Observables in +- CP asymmetry (time-dependent) Extra weak phase –b, strong phase d, and |P/T|, modify a by k • : from isospin analysis L.Lanceri - B-Factories: Physics Reach - CSNI

  16. BABAR Belle 2 Belle 1 BaBar and Belle: Spp and Cpp With incomplete information (no isospin analysis): • Measure Spp and Cpp from both sinDmDt and cosDmDt terms . • Compare with predicted Spp and Cpp values for given a, b, |P/T|, and d. Assume for instance: cf. Gronau and Rosner, Phys. Rev. D65, 093012 (2002) L.Lanceri - B-Factories: Physics Reach - CSNI

  17. Results and extrapolations forsin2eff Results (0.08 ab-1) Extrapolated errors (BaBar) L.Lanceri - B-Factories: Physics Reach - CSNI

  18. sin2: isospin analysis (Gronau & London) Need flavor tagged rates for +-, 0, 00 BaBar: L.Lanceri - B-Factories: Physics Reach - CSNI

  19. Grossman-Quinn bound: BaBar, extrapolations: vs BF(00), at fixed Luminosity Upper bounds on = 2eff-2 BaBar, present data: Small gain with lumi Most powerful at small BF L.Lanceri - B-Factories: Physics Reach - CSNI

  20. BR(B`gp`p0) = 4.1x10-6 BR(B0gp+ p-) = BR(B0gp+ p-) = 4.7x10-6 Isospin analysis: projections - 1 • Sensitivity to : toy MC with BaBar detector • Assumptions (example): NB: 4-fold ambiguity ! <BR(Bgp0p0)> = 2.0x10-6 L = 0.5 ab-1 L = 2.0 ab-1   L.Lanceri - B-Factories: Physics Reach - CSNI

  21. Isospin analysis: projections - 2 • BaBar sensitivity on : summary • (4-fold ambiguity not included) • Assumptions: • 00 reconstruction efficiency: rec = 0.18 • For each B tagging category: • Tagging performance , D = 1-2w • Bkgd effective cross sect. B (106) L.Lanceri - B-Factories: Physics Reach - CSNI

  22. Quasi-2-body B0  analysis hep-ex/0207068 Acp 81.9 fb-1 L.Lanceri - B-Factories: Physics Reach - CSNI

  23. B0+– - B0–+ Interference Region B0+– - B000 Interference Region 3-body (+-0) Dalitz analysis for  • 11 parameters (“fundamental”): • remove overall phase & normalization: 9 parameters Suffers from mirror solutions • 10 parameters (“amplitudes”): • remove overall phase & normalization: 8 parameters • obtain fundamental parameters from subsequent fit. No mirror solutions. Does not depend on particular weak phase decomposition …work in progress L.Lanceri - B-Factories: Physics Reach - CSNI

  24.  at the B factories • sin(2) from fully/partially reconstructed B  D(*) • Analysis in progress • Rates and asymmetries in B   K, KK • Require theoretical assumptions • Promising developments: 3-body decays, Dalitz analysis (work in progress) • B  D(*)K(*), D(*)Ks, DKs, D(*)K(*), … • Most advanced analysis in BaBar: B-gD0(CP)K- • Sensitivity extrapolations from preliminary results 81.2 fb-1 L.Lanceri - B-Factories: Physics Reach - CSNI

  25. g (Gronau-London-Wyler)  from B-gD0(CP)K- Observables: n1, p1, n2, p2 Theor. parameters: , r,  L.Lanceri - B-Factories: Physics Reach - CSNI

  26.  from B-gD0(CP)K-: projections Recent experimental results (BaBar) Toy MC projections: (Fit unreliable for r = 0.1) r=0.3 (0.5 ab-1), sin2g = 0.75  fit: sin2g = 0.720.23, g = (59.910.2)o r=0.2 (2ab-1), sin2g = 0.75  fit: sin2g = 0.710.14, g = (58.57.4)o r=0.2 g=60o Dd=30o (2ab-1) ACP=0.174 0.031 L.Lanceri - B-Factories: Physics Reach - CSNI

  27. Vcb (Vub) (u) |Vtd/Vts|2 (,…) CKM Triangle: sides

  28. Breco Brecoil D(*) Y(4S) l p n |Vub| from fully tagged SL decays Semileptonic decays on the recoil of fully rec. B (~1KB0 /fb-1, ~2KBch. /fb-1) To separate bul MX(< MD) ( ~ 60-80%) (or other variables: P*l, q2) Xu L.Lanceri - B-Factories: Physics Reach - CSNI

  29. projected errors for|Vub| Selection: One B reconstructed in D(*)X Lepton momentum and neutrino mass Kaon veto, charge balance Fit Mx with constraints MX distribution fit: buln, bcln, background Errors: Statistical L(ab-1) = 0.08 0.5 2.0 10 sstat(%) = 7.0 2.8 1.4 0.6 Experim. Systematic ~5% (now)  2.5% (bcln bkgd) Theoretical ~ 9% (s(mb)=90MeV)  5% (buln above cut) Mx cut, b quark Fermi motion from b  s, Mx bins Further improvements from lattice QCD, restricted phase space Mx (GeV) L.Lanceri - B-Factories: Physics Reach - CSNI

  30. Towards Vtd/Vts Extrapolation 0.5 ab-1 2 ab-1 From experience gained with present data 0.5 ab-1 2 ab-1 Significant gain if one can reduce the background by factor 2 10% error due to long range effects to be compared to 6% for Dmd/Dms L.Lanceri - B-Factories: Physics Reach - CSNI

  31. QCD penguin bu tree EM penguin Rare B decays EW penguin leptonic

  32. Charmless decays: Direct CP violation? Time-integrated CP asymmetries: No evidence for direct CPV yet Theoretical expectations: Tree + Penguin: ACP 10% Pure Penguin: ACP 1% Present sensitivity (most channels) statACP 10% systACP 12% Charge asym. L.Lanceri - B-Factories: Physics Reach - CSNI

  33. Signal Box Sideband m(D0)Rec-m(D0)PDG (m(D0)) Remaining neutral Energy (GeV) EW Penguins (BaBar): Exclusive measurements: 85M BB pairs Inclusive (bsl+l-) in progress Preliminary Theory (SM): B(B+K+)  3.8 x 10-6 56M BB pairs, fully reco. SL tag 2 events observed (2.2 bkgd expected) B(B+K+)  9.410-5 (90% CL) L.Lanceri - B-Factories: Physics Reach - CSNI

  34. Leptonic decays (BaBar) • Already published, to be updated (Run1+2) • BF(B ) < 1.7 10-6 (90% CL); int.lumi. 19.4 fb-1 • ICHEP 2002 (Run1+2): • BF(B  e+e-) < 3.3 10-7 , BF(B  +-) < 2.0 10-7 , • BF(B  +e-) < 2.1 10-7 (90% CL) • New analyses on B+ + (Run1+2),with: • Lepton tag or Fully reconstructed hadronic tag • Sensitivity competitive with existing exptal limits (LEP: 5.7  10-4) L.Lanceri - B-Factories: Physics Reach - CSNI

  35. Some extrapolated yields (BaBar) • Extrapolated yields for B+ + andB+K+ Present analysis: backgrounds:  280 events in 80fb-1 K 2 events in 56MBB pairs L.Lanceri - B-Factories: Physics Reach - CSNI

  36. Rare decays - Summary Projections from Snowmass 2001: reconstructed events Efficiencies from BaBar/Belle; some numbers should be updated (*) “B exclusive tag” (assuming   0.2%) Asymmetries! Rates… L.Lanceri - B-Factories: Physics Reach - CSNI

  37. Conclusions & Outlook • B factories discovered CP violation in B decays and are measuring sin2 with increasing accuracy • Each of the two B factories integrated a luminosity of about 0.1ab-1 and should integrate 0.5ab-1 by 2006; depending on the machine upgrade options, about 2ab-1 per experiment could be within reach by the end of the decade • Such an increase in integrated luminosity will significantly extend the physics reach of the B factories, both for the Unitarity Triangle, and for rare B decays • Other topics, including charm and tau physics, are part of the physics program (see backup slides) L.Lanceri - B-Factories: Physics Reach - CSNI

  38. Backup slides

  39. “short distance”  x Vcd,cs W- Vud,us c u D0 d,s d,s D0 u c V*ud,us W+ V*cd,cs “long distance”  -iy K-, D0 D0 K+,+ Charm An example: D mixing Very small in the S.M. • 2  additional suppression  A window for new physics Sensitivity estimate (BaBar) 1, including statistical and systematic uncertainties L.Lanceri - B-Factories: Physics Reach - CSNI

  40. lepton number is violated in many extensions of the S.M. (present limits, O(10-6) are close to some model predictions) tau Another example: lepton number violation S.M., extended to include n mixing and mass: BR(t) ~O(10 - 34) BaBar sensitivity, projections: L.Lanceri - B-Factories: Physics Reach - CSNI

  41. B physics: accelerators Hadron colliders: Higher cross sctions, but: higher bkgd, lower efficiency B-factories: Luminosity is the critical factor L.Lanceri - B-Factories: Physics Reach - CSNI

  42. BaBar Detector EMC 6580 CsI(Tl) crystals e+ (3.1GeV) 1.5T solenoid DIRC (PID) 144 quartz bars 11000 PMs Drift Chamber 40 stereo layers e- (9GeV) Silicon Vertex Tracker 5 layers, double sided strips Instrumented Flux Return iron / RPCs (muon / neutral hadrons) • SVT: B vertex z resolution ~70 microns • Tracking: (pT)/pT= 0.13%  pT0.45% • DIRC: K- separation > 3.4 for P < 3.5GeV/c • EMC: E/E = 1.33%E-1/4 2.1% L.Lanceri - B-Factories: Physics Reach - CSNI

  43. CP asymmetries: sensitivity • Error on the diluted CP asymmetries (Aobs= DACP) • Number of events: • Efficiencies: • Dilutions: • B factories • Small cross section: • higher efficiencies and better dilutions   D2 L.Lanceri - B-Factories: Physics Reach - CSNI

  44. Bflav Mixing sample BaBar, sin2b: “golden” modes, now CP states with charmonium: to measure sin2 2641 tagged events on-peak: 81.9 fb-1 off-peak: 9.6 fb-1  89 M BB pairs c1 Ks J/Y Ks (Ks p+p-) Flavor states: to measure mixing and D, R J/Y Ks (Ksp0p0) 25375 events Y(2s) Ks J/Y K*0 (K*0  Ksp0) J/Y KL hcp=+1 L.Lanceri - B-Factories: Physics Reach - CSNI

  45. CP violation: sin2 sin2b = 0.741  0.067 (stat)  0.034 (syst) hcp=-1 hcp=+1 sin2b = 0.755  0.074 sin2b = 0.723  0.158 PRL 89 (2002) 201802 L.Lanceri - B-Factories: Physics Reach - CSNI

  46. sin2 - K0S hep-ex/0207070 • Pure QCD Penguin, sensitive to New Physics contributions • In the SM, time-dependent asymmetry in K0S measures sin2b B  K0S 51 events From 87 M B pairs: L.Lanceri - B-Factories: Physics Reach - CSNI

  47. If no penguins: we measure -sin2b + 407 events sin2 - J/0 hep-ex/0207058 L.Lanceri - B-Factories: Physics Reach - CSNI

  48. sin2 - ’K0S B  ’K0S 203 events Large Penguin contribution expected ! preliminary L.Lanceri - B-Factories: Physics Reach - CSNI

  49. sin2 - D*D* (bccd) hep-ex/0207072 • D*+D*-, is not a CP eigenstate (L=0,2 and L=1) • CP odd fraction R  • .Transversity analysis B0D*+ D*- CP-odd fraction R = 0.07  0.06  0.03  mostly CP-even ! L.Lanceri - B-Factories: Physics Reach - CSNI

  50. + • We measure : • Im(l+) • |l+| -sin2b Small ( < 0.1 T) penguin contribution expected Im(l+) = 0.31  0.43 (stat)  0.13 (syst) -sin2b = -0.741  0.067 |l+| = 0.98  0.25 (stat)  0.09 (syst) From 126  12signal events sin2 - D*D* preliminary L.Lanceri - B-Factories: Physics Reach - CSNI

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