B, λ B and Charm results from the Tevatron

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B, λ B and Charm results from the Tevatron. Physics in Collision: Zeuthen, June 27 2003. Farrukh Azfar, Oxford University (CDF). Overview of this presentation :. Tevatron performance & Beauty Physics at the Tevatron 2) CDF and D0 detectors and triggers - PowerPoint PPT Presentation

Transcript of B, λ B and Charm results from the Tevatron

  • B, B and Charm results from the TevatronFarrukh Azfar, Oxford University (CDF)Physics in Collision: Zeuthen, June 27 2003

  • Overview of this presentation:Tevatron performance & Beauty Physics at the Tevatron

    2) CDF and D0 detectors and triggers

    Data from various Triggers at CDF and D0

    Physics Results : Masses and Lifetimes of B hadrons Tests of Heavy Quark Expansion (HQE)

    4) Physics Results: Charm : masses, search for CP violation (CPV) & Flavour Changing Neutral Current (FCNC)

    5) Physics Prospects: CP violation, Bs mixing (xs=Dms/G) and Bs width difference (DGs)

    6) Conclusion and Summary

  • Tevatron pp collider upgrade & performancePerformance Improvement:-Collision rate: 3.5 ms 396 ns-6x6 bunches 36x36 bunches-Center of Mass energy: 1.8 1.96 TeV/c2-Peak luminosity : 2.4x1031 4.4 x1031cm2s-1(Below target by x4, steadily improving)Run-I (1992-1996) -Accumulated Ldt=110 pb-1

    Run-IIa -Goals are Ldt=2fb-1 (x20 Run-I)

    Run-II Tevatron Upgrades: Main Injector -New Injection stage for Tevatron -Higher proton intensity -Anti-proton transfer efficiency increased -Anti-proton recycler (work in progress)

  • Data taking performance CDF & D0CDF integrated luminosity:-Delivered 230pb-1 of which-175pb-1 to tape, of which-70 pb-1 has important systems on(eg. Silicon) B-physics analysesD0 efficiency:-50 pb-1 B-physics analysesPhysics Results in this talk are from ~70pb-1 @ CDF and ~50pb-1 @ D0

  • Why Beauty at the Tevatron ?s(bb) at (4S) = 1nb (B-factories)s(bb) at Z0 = 7nb (LEP)s(bb) at pp (1.96TeV/c2)=150mb (Tevatron Experiments)

    More B @ Tevatron but inelastic s at tevatron is 103 x s(bb) -Must select b-data online, key: appropriate detector & triggers -Rewards: can produce all B-hadrons eg B, B0, Bs, Bc , b etc (unlike B-factories) & higher s than at Z0

    Signatures for B Selection & use at CDF & D0:

    -High PT leptons from b mnX or b enX (CDF & D0) -Di-leptons from B J/yX, J/y m+m- (CDF & D0) -Utilize long B and charm lifetimes large impact parameter (IP) of daughter tracks (CDF, D0 in progress)

  • The CDF & D0 Detectors in Run-II

    New: Time of Flight (TOF): some hadron ID New: Silicon (SVT) online Si tracker: Select high IP tracks from b and c @ trigger level (First time at a hadron collider !)

    Improvements over Run-I-Silicon Detector : 3-D tracking, 5 layers: B vertex, track IP resolution,-Faster Drift Chamber : Momentum measurement-Greater muon coverage : Select b, c mNew : 2T Super conducting MagnetNew: Silicon tracker (vertex, track IP resolution) New: Fiber tracker : MomentumNew: Si Track Trigger (displaced vertices) (Coming soon)Improvements over Run-I-Calorimetry and faster readout-Upgraded muon system.CDF DetectorD0 DetectorD0 has a magnetic field, and is able to pursue a competitive B-physics program as well !

  • Data Samples: The J/y m+m- at CDF and D0 (Run-II)0.5M at CDF (70 pb-1) 75K at D0, completely new capability ! (40 pb-1) Two Fully Reconstructed B-hadron J/y states at CDF &D0B J/y KS: CDF:220, D0:45 (Run-II) (D0 had none in Run-I)LB J/yL : CDF:53, D0:16 (Run-II)

  • Data Samples: B and Charm Using the high Impact Parameter (IP) (Hadronic) triggerSelect events by requiring : -2 tracks with IP>100 mm - track PT > 2GeV/c - sum 2-track PT > 5.5 GeV/c0.5M Charm decays at CDF 10-20% come from B: Great Potential for B and Charm Physics, opens at least as many avenues as J/y trigger

  • Data Samples: B(+)l+uD decays using hybrid triggerOne lepton (PT>3 GeV/c) & one high IP (>120mm)track:-High IP track means we can go lower in lepton PT-Statistics much higher than Run-I (lower PT thresholds)(x4-5 increase in statistics)

    Used for:1) High statistics lifetime and mixing analyses 2) calibration samples for tagging (B+ l+nD) Drawback: worse vertex resolution due to missed neutrinoSome numbers:BglD0X (D0gKp): ~10000 events, BglD+X (D+gKpp): ~5,000 events also Bs decays (later)

  • Physics Results: lifetime, mass, from fully reconstructed BJ/y X modes: Standard Technique : Data from J/ym+m- di-muon trigger: - Reconstruct vertex - Calculate decay proper time, mass & errors- Fitting for Mass:fit mass only- Fitting for Lifetime:Fit mass and lifetime distributions in single stepAn Example B+ J/y K+ at CDF Technique applied to several decays : B+ gJ/y K+, B0 gJ/y K0* (K0* g Kp), Bs g J/y f (f gKK) & LbgJ/yL (Lgpp)Probability Density Function and normalization:

  • Physics Results: Bs J/y f, Lifetime and Mass:J/y m+m- and f K+K- (using di-muon (J/y) trigger): 1) Run-I: we had ~60 at CDF.2) Run-II: we have ~136 at D0 and CDF : Worlds largest sample of fully reconstructed Bs decays remains at the TevatronCDF: M(Bs) = 5365.5 1.29(stat)0.94 (sys) MeV/c2, D0: M(Bs) = 5360 5 CDF: t(Bs) = 1.26 0.2 (stat) 0.02(sys) ps, D0 lifetime analysis in progressFit has one lifetime (width) but this mode contains two lifetimes: CP even and CP odd BsWith higher statistics we can use angular variables & disentangle CP states & fit two lifetimes (widths)Why is the width difference interesting ?-Bs width difference DGs: predicted to be large ~10% -SM : DGs=A.xs (xs=Bs mixing Parameter)-If xs is large and DGs is small or vice-versa sign of new physics-SM CP violation in Bs J/yf ~3% if extra-SM CP violation phase =Sin2e then DG s,measured = DG s,SM.Cos2e (DGs and CPV are complementary)

  • Physics Results: LB, lepton+displaced track and purely hadronic data samples (have shown J/y mode already)b cl [pK] lProtons are easiest to separate using Time of FlightParticle ID in left plot using TOF and dE/dXb cp [pK] pLifetime in hadronic, hadron+lepton modes requirecorrection for IP cut bias & missing Expect results this summerNote on LBA search for CP violation in Baryon decays is plannedusing LB pp

  • Physics Results:Testing HQE: A summary of results:CDF (70 pb-1): t(B+ )= 1.570.070.02 ps using (B+ J/yK+) t(B0 )=1.42 0.090.02 ps using (Bd J/yK*0) t(B+)/t(Bd)= 1.11 0.09 (Run-II) t(Bs)/t(Bd)= 0.89 0.15 (Run-II) D0 (40 pb-1): t(B+ )=1.76 0.24 ps using (B+J/yK+) BELLE (PRL 88 171801 2002) using BdD(*)-(p+,r+), J/yKS,J/yK*0 and B+D0p+, J/yK+t(B+)/t(Bd)= 1.0910.0230.014BABAR : fully reconstructed decays

    Bd D(*)-(p+,r+,a1+), J/yKS,J/yK*0 and B+ D0p+, J/yK+t(B+)/t(Bd)= 1.0820.0260.012

    BABAR : partially reconstructed decays(BD,D* l n)t(B+)/t(Bd)= 1.064 0.031 0.026HQE Predicted B Lifetime hierarchy : tBc

  • Physics Results:Testing HQE: A summary of results:s(t(B+)/t(Bd)) surpasses theory: 1.067 0.027 (HQE) (@ both Tevatron and B-factories)s(t(Bs)/t(Bd)) doesnt (yet): 0.998 0.015 (HQE)

    Tevatron: Projection: s(t(Bs)/t(Bd) ) and s(t(Bd)/t(Lb))

  • Physics Results: Charm physics at CDF: Ds-D mass differenceDs - D mass difference2400 Ds and 1600 D in only 11.6 pb-1 of datam = 99.28 0.43 0.27MeV/c2In agreement with old world average:99.2 0.5 MeV/c2 (PDG: CLEO2, E691)and with recent BaBar result:98.4 0.1 (stat) 0.3 (syst) Mev/c2First Run-II publication from CDF-comparable with recent results1) Data Selected from the hadronic trigger2) Both Ds,D decay to fp with fK+K-3) Kinematics of both decays ~identical4) Simply measure difference

  • Physics Results: Charm physics at CDF: Search for Flavour Changing Neutral Current decay D0m+m- SM predicts a branching ratio (BR) of O(~10-13) for D0m+m-Some R-parity violating SUSY models predict branching ratios upto O(~10-6) CDF Result: BR(D0m+m) < 2.4x10-6 better than most recent world average:( PDG 90%CL: < 4.1 x 10-6 )Technique:D0p+p- BR is well known ~ identical acceptance to D0 m+m- 2) Use D0*D0p to tag D0 in D0K-p+ (thus no K vs p ambiguity)3) See how many ps fake ms per PT5) Look for D0 m+m- in same sample6) Subtract D0p+p- faking D0m+m- 0 events found in 2s searchwindowA similar analysis of the rare decay Bs m+m- establishes a 4s sensitivity to signal for branching ratios >3.3x10-6

  • Physics Results: Charm physics at CDF: Search for CP violation (CPV) in Charm decays:1) c and u quarks dont couple to t box diagram contributions are tiny2) CPV in charm decays due to interference in decay (direct CPV) 3) SM prediction O(0.1-1%) CP violation effects in Charm DecaysHow: Compare rate of Decay of D0, D0 to CP eigenstates f=K+K- and p+p-Method Using data from Hadronic Trigger-Collect D*D0p : sign of p tags flavour of D-Search for D0 K+K-, D0 p+p-, D0 p+p- & D0 K+K- Correct for tracking efficiency for + vs - p from D*D0p-Count number of decays in each mode after corrections

  • Physics Results: Charm physics at CDF: Search for CP violation in Charm decays:8320 D*D0p, D0 K+K- 3697 D*D0p, D0 p+p- First attempt at measuring CPV at CDF in Run-II93560 D*D0pwith D0K+p- Cross-check: Measure Ratio of Branching Ratios @CDF G(D0 p+p-)/G(D0 K+p-)=9.380.180.10% G(D0 K+K-)/G(D0 K+p-)=3.686 0.076 0.036%

    FOCUS: G(D0 p+p-)/G(D0 K+p-)=9.930.140.14% G(D0 K+K-)/G(D0 K+p-)=3.530.120.06%CDF accuracy is comparable and consistent with FOCUS (2003) and World average 2.880.15 (PDG)ACP(D0 (p+p-))= (PDG 0.51.6%)ACP(D0 (K+K-))= 2.12.6%)CLEO Result (2001) ACP(D0 (p+p-))= ACP(D0 (K+K-))= 1.9 3.20.8%

  • Mixing and CP violation (CPV) in B decays Same side taggingOpposite side taggingConcept: Look for charged tracks around reconstructed Bof interest, Higher e

    Look for m,e from B decayLook for p (K) from hadronization of B (Bs) Concept:Look forB on opposite sideof B of interest -Look for m,e -Look for p or K-Use weighted jet-charge Disadvantages: Opposite B not in acceptance (60%) or m