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Flavor Physics at the Tevatron

Flavor Physics at the Tevatron. Franco Bedeschi INFN - Sezione di Pisa. Flavor Physics at the Tevatron. OUTLINE. Main features of Heavy Flavor production at the Tevatron Experimental issues Basic signals and first round of results

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Flavor Physics at the Tevatron

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  1. Flavor Physics at the Tevatron Franco Bedeschi INFN - Sezione di Pisa F. Bedeschi, INFN-Pisa

  2. Flavor Physics at the Tevatron OUTLINE • Main features of Heavy Flavor production at the Tevatron • Experimental issues • Basic signals and first round of results • Masses, lifetimes, branching fractions and integrated CP asymmetries • Other results and future prospects • Baryons • Bc search • Rare decays, mixing • xs, DG, b, g F. Bedeschi, INFN-Pisa

  3. HF at the Tevatron • Very large production of b/c quarks at the Tevaton (ECM = 1.96 TeV)! • b/c-quarks masses much heavier than u, d, s, but small relative to <ŝ> • Mc ~ 1.5 GeV/c2 • sc ~ 500 mb • S/N ~ 10-3 • Mb ~ 5 GeV/c2 • sb ~ 100 mb • sb ~ 1 nb at B-factories, ~ 7 nb at LEP • S/N ~ 10-3 • 0.2 at B-factories, 0.14 at LEP F. Bedeschi, INFN-Pisa

  4. HF at the Tevatron NLO • Production more complex than in e+e- • s, t, u-channel and NLO~LO • Motion of CM of primary interaction • Larger spread over available phase space • Acceptance • Looser f and q correlation • No beam ECM constraint • HF hadron from hadronization of primary quarks • All types of b-hadrons produced • Looser momentum correlations • Beam renmant • More background from particles other than HF decays LO F. Bedeschi, INFN-Pisa

  5. Tevatron vs B factories • In the end comparable amount of usable Bu, Bd • Pt, h acceptance reduces TeV sample available • B factories luminosity higher • NOW  Tev: ~ 250 pb-1, Belle/BaBar: ~150 fb-1 • Tevatron environment more “difficult” • Incoherent b-pair production • Bs, Bc and HF baryons hard or impossible at B factories • Some measurements are possible only at the Tevatron • Eg. Bs mixing, Bc properties, …. • Other measurements are complementary • Eg. CP violation angle g Run 1 F. Bedeschi, INFN-Pisa

  6. Some History • First fully reconstructed B mesons observed at a hadron collider: • CDF 1992 (2.6 pb-1) • PRL 68, 3403 (1992) B+J/y K+ F. Bedeschi, INFN-Pisa

  7. Run 1 • Successful B physics program at Tevatron during run 1 First evidence of sin(2b) Lifetimes Mixing Integrated luminosity ~ 120 pb-1 F. Bedeschi, INFN-Pisa

  8. Run II: Tevatron 8.6 fb-1 • Peak luminosity: • 7x1031 • Delivered/on tape: • 500/400 pb-1 • Analyses based on • ~ 240 pb-1 > 2 x Run 1 4.4 fb-1 Base plan ~ no recycler Tevatron long range plan will deliver 4 – 8 fb-1 by end of FY 2009 F. Bedeschi, INFN-Pisa

  9. The Upgraded CDF Detector Central calorimeters Solenoid Central muon New Old Partially new Front end Trigger DAQ Offline TOF Endplug calorimeter Silicon and drift chamber trackers Forward muon F. Bedeschi, INFN-Pisa

  10. D0: side view Tracker : Silicon, Fiber, 2T Solenoid Preshower Calorimeters New Forward Muon System Old Partially New p p-bar Central Muon System 20 m Electronics Front End Electronics Triggers / DAQ (pipeline) Online & Offline Software F. Bedeschi, INFN-Pisa

  11. J/Y c b c W- s B K q q Tracks from B decay B/D meson Tracks from b fragmentation Primary vertex Tracks from underlying event Trigger is the key to B physics l - n • S/N ~ 10-3 need strong signatures • Leptons from SL decay: • ~10% for each mode • Large mass  large ptrel • Leptons from J/Y decay: • B  J/Y + X 1% • J/Y  m+ m-, e+ e- 6% each • Secondary vertex!: • ctD & ctB ~ 300 - 500 mm • Only way for had. decays W- b B c D q D q F. Bedeschi, INFN-Pisa

  12. CDF SVT trigger • Need dedicated impact parameter trigger • CDF SVT trigger operating since 2001 • D0 trigger still being commissioned Resolution Efficiency Online track impact param. 8 VME crates Find tracks in Si in 20 ms with offline accuracy s=48 mm 80% F. Bedeschi, INFN-Pisa

  13. p K K  p PID at CDF • Time of Flight • dE/dx in COT and SVX TOF: >1 K/π separationupto p=2 GeV dE/dx in COT K/π sep. >1.4@Pt>2GeV (was 1.2) 1.5 GeV/c dEdx in Silicon Vertex for low-pt tracks PLAN: combine them all ! F. Bedeschi, INFN-Pisa

  14. Run II Results • Large sample of J/y for both CDF and D0 (~2.5 M events at CDF) -- ~ 20 % from B decays • Calibrate mass scale • Clean samples of exclusive decays B J/y X F. Bedeschi, INFN-Pisa

  15. X (3872) FERMILAB-PUB-03/393-E X yield: 730 ± 90 cand. (11.6 s) • Search for Xyp+p- • Confirm signal from Belle Y(2S) m(pp) > 500 MeV M = 3871.3±0.7± 0.4 MeV hep-ex/0312021 F. Bedeschi, INFN-Pisa

  16. Bs m+m- Bd m+m- Background 1.05±0.30 1.07±0.31 Data 1 1 BR limit @95% C.L. 7.5 10-7 1.9  10-7 BR limit @90% C.L. 5.8  10-7 1.5  10-7 Rare decays: Bd(s) m+m- Best world result for Bs (improves CDF Run I x3) 1 event in the overlap region Slightly better results than Belle and BaBar for Bd • Muon Pt>1.5-3.0 GeV, |eta|<0.6 • “Blind” analysis: cuts optimized before looking at the signal region 2.0  10-7 1.6  10-7 F. Bedeschi, INFN-Pisa

  17. R. Dermisek et al., hep-ph/0304101 SO(10) 7.510-7 Bs m+m- implications for SUSY R. Arnowitt et al., PLB 538 (2002) 121, new plot by B.Dutta R-parity violating New limit excludes significant amounts of the previously allowed SUSY models parameters - Expect ~10-7 with 1fb-1 F. Bedeschi, INFN-Pisa

  18. Run II Results • Precision mass measurements: • M(Bu) = 5279.10±0.41±0.34 MeV/c2 • M(Bd) = 5279.57±0.53±0.30 MeV/c2 • M(Bs) = 5366.01±0.73±0.30 MeV/c2 • M(Lb) = 5619.7 ± 1.2 ± 1.2 MeV/c2 Current world best values F. Bedeschi, INFN-Pisa

  19. Run II Results • CDF Lifetimes measurements: • D0 has best measurement of ratio of Bu and Bd lifetimes: • t(Bu)/t(Bd) = 1.093±0.021±0.022 • (CDF: • Bu/Bd = 1.080  0.042 • Bs/Bd = 0.890  0.072) • Consistent and only slightly worse than BaBar PDG result New technique used fitting the ratio of lifetime distributions in semileptonic decays F. Bedeschi, INFN-Pisa

  20. Run II Results Example of lifetime bin • D0 lifetime ratio determination: • m-D*+X: mostly Bd • m-D0X: mostly Bu • Fit ratio r=N(mD*)/N(mD0) in 8 visible lifetime bins • Account for feed-down from D** using MC • Shows power of large statistics semileptonic samples F. Bedeschi, INFN-Pisa

  21. Toward DGs • Lifetime difference of two CP eigenstates of Bs can be large in SM ~ 10% • Related to Dms: DGs ~ 3.7x10-3Dms • Easier to measure as Dms gets harder! • Dms = 24 ps-1  DGs /Gs ~ 15 % • Best measurement from comparing a CP specific decay with a flavor specific decay (roughly 50-50) • e.g. CP specific: BsJ/y f mostly CP even • Need to measure fraction of CP even with angular analysis • e.g. Flavor specific: BsDsp, BslnDs F. Bedeschi, INFN-Pisa

  22. Run II Results • Polarization analysis consistent with B factories for BdJ/y K*0 • Best measurement for Bs  J/y f • Important step toward DGs • A0, A// are CP-even ~ 75% BdJ/K* F. Bedeschi, INFN-Pisa

  23. The Bc, rediscovered… CDF Run1 Box still closed for blind analysis of J/yp (10% of J/y ln) F. Bedeschi, INFN-Pisa

  24. Run II Results • Large samples of hadronic exclusive decays of all beauty and charm hadrons at CDF • Measure relevant BR • Start understand how to measure lifetimes • Prime samples for mixing measurements, in particular Bs • Significant samples of 2 body decays • Measure BR’s and integrated CP asymmetries • Basic samples for future g measurements F. Bedeschi, INFN-Pisa

  25. Run II Results: D0 BR and ACP Best measurements! Better than FOCUS 03 • Clean sample of ~ 200 k D0 from D*D0psdecay • Charge of soft pion tags initial D0 type BR(D0KK)/BR(D0Kp)= 9.96 ±0.11(stat) ±0.12(syst) % BR(D0pp)/BR(D0Kp)= 3.608±0.054(stat) ±0.040(syst) % ACP(D0KK) = 2.0 (1.7) ±1.2 (stat) ±0.6 (syst) % (* norm. to DKp) ACP(D0pp) = 1.0 (0.5) ±1.3 (stat) ±0.6 (syst) % pp KK Kp F. Bedeschi, INFN-Pisa

  26. Run II Results • Now going for BR and ACP of D+ πππ - No experiment ever had >1500 ev • Expect ~6k events after flavor tag • BR known at 10% will become 1% • Unique possibility to see ACP in Charm ~190 pb-1 55,000 events ! F. Bedeschi, INFN-Pisa

  27. Run II Results BdD-+ - MC templates used to fit mass spectrum. - BDK is another mode of interest for CP analysis. F. Bedeschi, INFN-Pisa

  28. bc with cpK • Backgrounds: real B decays • Reconstruct p as p: BdDp+K+ppp+ • Use MC to parametrize the shape. • Data to normalize the amplitude • Dominant backgrounds are real HF • proton particle ID (dE/dx) improves S/B Fitted signal (65 pb-1): Now 361±28 with 195 pb-1 Cleaner with PID ! Measure: New Result ! (based on 65 pb-1) BR(Lb Lcp) = (6.0 1.0(stat)  0.8(sys)  2.1(BR) ) x 10-3 F. Bedeschi, INFN-Pisa

  29. More Baryons:First observation of X0c,X+c p X0c X- X+c F. Bedeschi, INFN-Pisa

  30. Run II Results BsDs-+ - BsDs-+ is the golden mode for measuring xs. - Fully reconstructed mode for minimal uncertainty in the boost of the Bs. F. Bedeschi, INFN-Pisa

  31. kinematics & dE/dx to separate contributions Bh+h m = 5.252(2) GeV/c2  = 41.1(1.9) MeV/c2 Simulation Fitted contributions: BdK BsKK Bd BsK  M() First observation of BsK+K!! Result: Measure ACP F. Bedeschi, INFN-Pisa

  32. Unfolding two body decays • Unfolding: • Kinematics (momentum ratio) • Mpp vs q1*(1-p1/p2) • Different correlations for various species/decay channel • dE/dx in Central Tracker F. Bedeschi, INFN-Pisa

  33. Latest B->hh BR& direct ACP Bd = 160  27 BsKK = 225  29 BsK = 28  25 BdK = 542  30 • Substantial yields in 180pb-1 • Bd yields = 80fb-1 Babar • RAW yields for the moment • Update of LP03 result at ICHEP04 Very preliminary ACP(BdK) = -0.08  0.07 • Direct Acp(Kπ) to 7% (Babar 5%@same yield) • BR(BsKK) to 15% -> Constraints CKM (angle ) • Largest fully reconstructed Bs sample, CP eigenstate  s F. Bedeschi, INFN-Pisa

  34. Bhh expectations CDF 180 pb-1 Current single best measurement Scaling from current yields F. Bedeschi, INFN-Pisa

  35. B+K+ BR • Pure-penguin, b->sss decay • Sensitive to Vts and NP • BR & direct-ACP (180pb-1) ACP F. Bedeschi, INFN-Pisa

  36. Another B->sss penguin process • QCDF expectation: 3.68 10-5 First Observation ofBs ff Good S/B ! 5 significance F. Bedeschi, INFN-Pisa

  37. D2 [%] CDF-II CDF-I Soft muon 0.7  0.2 Soft electron in progress e+µ 2.10.5 Jet charge 0.4  0.02 * 2.2  1.3 Same Side 1.0  0.5 2.1  0.5 Opp. side kaon in progress N/A Same side kaon in progress N/A B Flavor Tagging OST (opposite side tagging): B’s produced in pairs  tag flavor of opposite B JETQ:sign of the weighted average charge of opposite B-Jet SLT:sign of soft lepton from decay of opposite B SST (same side tagging): B0(B0)is likely to be accompanied by a+() Search for the track with minimum PTREL Kaon taggers (new in CDF): OST (K from bcs transition) SST (K from fragmentation) • Evaluation in progress, expectations between 5-10% • Learning process in runII no faster than runI... *simpler algorithm F. Bedeschi, INFN-Pisa

  38. First Bd mixing results • CDF: Same Side Tagging • Exclusive samples • D0: m tagging • Semileptonic sample CDF D0 md=0.5060.055(stat)0.049(syst) ps-1 Tagging efficiency: 4.8 +/- 0.2 % Tagging purity: 73.0 +/- 2.1 % (D = 0.46) F. Bedeschi, INFN-Pisa

  39. Hadronic Yields for Bs mixing BR paper draft • Currently ~1.5pb of hadronic + ~1pb needing reflection cleanup Need 2pb and D2= 5% for 5 sensitivity up to 24ps-1 in 3.2 fb-1 • - xs is the most complex of all • B measurement • Need to combine many ingredients F. Bedeschi, INFN-Pisa

  40. Dms (ps-1) Bs mixing reach • Assumptions • Yield • 2k ev./fb-1 • From data • Flavor Tagging • eD2 = 5% • Pessimistic • Needs work • Time resolution • 50 fs • Need L00 • Signal/Noise • 2/1 • Data is better Go beyond SM preferred range: 5s measurement if Dms = 18 ps-1 with 1.7 fb-1 5s measurement if Dms = 24 ps-1 with 3.2 fb-1 F. Bedeschi, INFN-Pisa

  41. Conclusions • Tevatron is finally delivering luminosity • Experiments are accumulating data of excellent quality • D0 is in business thanks to new magnetic tracking • CDF’s secondary vertex trigger is a major success • Wealth of new results from fully hadronic decays promises a very interesting future! • Analyses involving flavor tagging are starting now and still need optimization of the basic tools • Results on Bs mixing and g require statistics at the fb-1 level. This will take at least until 2005 F. Bedeschi, INFN-Pisa

  42. Backup slides F. Bedeschi, INFN-Pisa

  43. Semileptonic samples • CDF/D0 have large samples: • Lifetimes need refinement of systematics • Mixing measurements will follow Bs F. Bedeschi, INFN-Pisa

  44. D cross section • Get prompt charm fraction from study of D impact parameter • Fprompt ~ 80-90 % varies with D species F. Bedeschi, INFN-Pisa

  45. D meson signals D0Kp • Huge D samples: sraw ~ 10 nb • Use D*Dps for cleanup • ps gives sign of kaon + Dm • Measure BR of suppressed 2 body decays to ~PDG accuracy • Measure CP asymmetries D0pp ACP=2±1.7±0.6 % D0KK ACP=3±1.9±0.6 % F. Bedeschi, INFN-Pisa

  46. b-decay: Bs mixing (prospects) • Signal (N): • Need all charged hadronic mode for resolution and statistics  secondary vertex trigger is essential • Bs Dsp, Ds 3p  • D+s  f p+, K0* K+, K0S K+ • Expectations for Run IIA in 2 fb-1: • 20,000 events (P-909) • 75,000 Yellow Book • Realistic ~7,000 • S/B: • ~ 1:1 from Run I extrapolations • Assume 1:2 – 2:1 range • Small effect on significance CDF preliminary Run II data Few pb-1 F. Bedeschi, INFN-Pisa

  47. b-decay: CP violation • As usual one measures: • Aobs(t) = D ACP(t) = Dsin(2b) sin(Dmdt) • Important to calibrate dilution with mixing analyses • Typical CP eigenstates have small Branching Ratio’s ~ 10-5! • Large b x-section at Tevatron is very useful • CDF Run 1 measurement is not competitive with B-factories, but it is very useful to estimate our future capabilities in Run II Measurements of sin(2b) PDG 2003 F. Bedeschi, INFN-Pisa

  48. + 0.37 • sin(2b) = 0.91 - 0.36 b-decay: CP violation • CDF Run 1 result is based on: • ~ 400 B0 J/y K0S • All available taggers: • Opposite side: lepton, Jet-charge • Same side: pion charge correlation • Result: ~ 400 B  y K0S Asymmetry Vs. lifetime F. Bedeschi, INFN-Pisa

  49. + + 2 1 x 1 N B d b » d ( sin (2 ) ) x N e 2 D N d b-decay: CP violation (prospects) • Extrapolation based on analytic formula for the error on the time integrated asymmetry: • In addition we account for improvements made by studying the time evolution • Expectations in 2 fb-1: F. Bedeschi, INFN-Pisa

  50. D0mm • Rare decay D0mm • SM: ~ 3x10-13 • R-violating SUSY: 3.4x10-6 • Best so far: 4.1x10-6 • Beatrice/E771 • CDF limit: 2.5 (3.3)x10-6 @ 90 (95)% CL • Luminosity used 63.5 pb-1 • Method: • Yield of D+* D0p  [mm] p relative to D+* D0p  [pp]p • ~ 1x10-7 by end of run II Phys. Rev. D68, 091101 (2003) F. Bedeschi, INFN-Pisa

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