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“Charm and Beauty at the Tevatron”

Explore the physics of charm and beauty particles at the Tevatron, including cross sections, lifetimes, CP asymmetries, and rare decays. Learn about the upgrades to the CDF and D0 detectors and the status of data taking.

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“Charm and Beauty at the Tevatron”

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  1. “Charm and Beauty at the Tevatron” Jack Cranshaw Texas Tech University For the CDF and D0 Collaborations Charm and Beauty at the Tevatron

  2. Why Do B Physics at the Tevatron? ECM=1.96 TeV • Large Cross Section! • Produce bottom mesons with all flavor combinations as well as bottom baryons. • Bc, Lb, b, ... • Multipurpose detectors CDF and D0 capable of reconstructing many B final states. • Experience with a 110 pb-1 of Run I data (1992-1996) Charm and Beauty at the Tevatron

  3. CDF and D0 Upgrades • D0 • Faster readout • Upgraded muon system. • New Inner tracking (silicon tracker, fiber tracker) • Si Track Trigger (displaced vertices) • CDF • Faster readout electronics. • Extended muon coverage. • Faster, larger silicon vertex tracking system. • Displaced vertex trigger (SVT) Charm and Beauty at the Tevatron

  4. Status of Data Taking • Peak Run II luminosity so far 4.5 X 1031 cm-2 s-1 • Approximately 150 pb-1 on tape with a variety of triggers and detector conditions. • Goal for Run IIa: 2fb-1 Results presented here based on ~80 pb-1 (CDF) and ~40 pb-1 (D0) Charm and Beauty at the Tevatron

  5. B Triggers and data samples Conventional New at CDF, Coming to D0 2-Track Trig. 2 Tracks with pT > 2 GeV SVT IP > 120 mm pT1+pT2 > 5.5 GeV Collected ~70 pb-1 ~ 0.5MD0Kp signal Fully hadronic modes • DiMuon (J/) • 2 central muons • PT() > 1.5 GeV (Run I: > 2 GeV) • Trigger on J/ymm • Collected ~ 70 pb-1 • ~ 0.5M J/ymm signal • J/ modes down to low PT(J/)(~ 0 GeV) Displaced track + lepton (e, ) 1 muon/electron pT>4 GeV 1 other track pT>2 GeV SVT IP>120 mm M(l-Track) < 5 GeV Collected ~70 pb-1 ~ 0.5M BlX signal Semileptonic modes • Rich program for charm and bottom physics • BS mixing • CP asymmetries • Rare decays • - High statistics lifetime • tagging studies, mixing - sin 2b - Masses, lifetimes - Quarkonia, rare decays Charm and Beauty at the Tevatron

  6. The Silicon Vertex Tracker (SVT) Read out Silicon detector & Reconstruct tracks at 10’s of kHz! Silicon Vertex Tracker (SVT) Includes 33m beamspot =48m Rate reduction: O(10-1) for 1 track d0>120 m O(10-2) for 2 tracks d0>120 m Charm and Beauty at the Tevatron

  7. Physics Program • Stage 1 ( ≤ 200 pb-1) • Charm physics • Cross sections, branching ratios • Lifetimes and masses • Bs, Lb properties • Stage 2 (200-500 pb-1) • First Bs mixing limit/measurement • Bc properties • CP measurements in the B system. • Stage 3 (500+ pb-1) • CKM angle g • DGs from Bc J/y f, DsDs •  Bc J/y f • B baryon spectroscopy (Xb, …) Stage 1 discussed in this talk Charm and Beauty at the Tevatron

  8. World Class Charm Program Charm and Beauty at the Tevatron

  9. Quarkonium 500K events 75K events • Dimuon states easy to trigger on and reconstruct. • Understand energy loss corrections. • Many B mesons decay to J/y X. Charm and Beauty at the Tevatron

  10.  and Bottom Baryons • Can reconstruct many charmed and bottomed baryons: m,t, G • Lc, Lb, Xb • Use all three trigger paths, e.g. • Lb J/y L • Lb Lc+  Lc+ p • Lb Lc+- Lc+ p World’s Largest Sample of Lb’s. Charm and Beauty at the Tevatron

  11. Kpp D0p Prompt Charm Production • Run I indicated poor theoretical understanding of flavor production mechanisms • Measure integrated and differential cross section for D0, D± D*±, Ds±. Kp Charm and Beauty at the Tevatron

  12. J/y Cross Section Extends to pT=0 • Lower pT thresholds allow measurement of dsdpT to pTy= 0. • First measurement of this type at hadron collider. , |h| < 0.6 Charm and Beauty at the Tevatron

  13. pTRel +jet jet b Jet Cross Section at D0 • Run I b-jet xsec results 2-3 times higher than predictions Strategy: Measure +jet cross-sectionExtract b-content using PTRel Data selection & kinematic cuts • pT >6 GeV/c, || <0.8 • |hjet| < 0.6 • ETcorr>20 GeV • 0.5 cone jet • dR(jet,m)<0.7 • 3.4 pb-1 of data Charm and Beauty at the Tevatron

  14. b Jet Cross Section Data unsmeared using ansatz function Dominant error is due to jet energy scale • Uncertainty due to • b quark mass • renormalization/ • factorization scale • pdf’s • fragmentation functions • Based on NLO calculations • and applied to Pythia (not fully corrected for lepton losses and branching ratio) Consistent with Run I result Charm and Beauty at the Tevatron

  15. m m m K+ K+ K+ K- Bs p- B0 B+ m m m B Meson Masses B+gJ/y K+ ~ 640 signal events (>1000 events with loose selection) B0gJ/y K*0 (gKp) ~ 220 signal events Normalization mode for sin2b analysis BsgJ/yf (gKK) ~75 signal events Golden mode for DGs measurement m=5365.50±1.29±0.94 MeV/c2 PDG: 5369.6 ± 2.4 m=5279.32±0.68±0.94 MeV/c2 PDG: 5279.0 ± 0.5 m=5280.30±0.92±0.96 MeV/c2 PDG: 5279.4 ± 0.5 Charm and Beauty at the Tevatron

  16. The Bs Meson • In 2002 PDG, 65 pages for Bu±, Bd0 modes/ properties, 3.5 pages for Bs0 modes/ properties. • Only four measured branching fractions. • Mass states and mixing similar to Bd. Gives access to |Vts| CKM element. • Provides means of measuring angles a and g of unitarity triangle, especially when combined with measurements of the Bd. • Of Particular Interest • Bs J/yf • Bs • BsK • Rare decays, e.g. Bsmm Dms and xs = Dms/Gs still unmeasured Charm and Beauty at the Tevatron

  17. = 0.42±0.11±0.11±0.07 Bs Yield and Branching Ratio • Need to understand Bs yield for triggers/physics. • Look at relative yield • Using values for fs/fd and Br(Bd D+ p) from the PDG we measure the BR(BsDs +p) Charm and Beauty at the Tevatron

  18. Inclusive B  J/y X Lifetime J/y B B through  t=1.5610.0240.074 ps D0 (40 pb-1)t=1.5260.0340.035 ps CDF (18 pb-1) PDG: t= 1.564  0.014 Charm and Beauty at the Tevatron

  19. = 0.89  0.15 = 1.11  0.09 B Meson Lifetimes B+gJ/y K+ B0gJ/y K0* (K0* g K+p-) Bsg J/yf (fgK+K-) PDG: 1.083±0.017 D0 results coming soon Charm and Beauty at the Tevatron

  20. D0 Signal for CP Asymmetry p Kp KK • SM predicts only small rates (0.1-1%) of mixing and CP violation in charmed meson decays. • Good place to look for non-SM physics • Measure relative branching fractions of D0(D0bar) decays for D0’s from D*+ D0p decays. • Use the sign of the soft pion as a flavor tag to measure ACP. Other D0 pp Charm and Beauty at the Tevatron

  21. Relative Branching Ratios CP Violation in D0 Decays • Relative branching fractions in agreement with previous measurements. • ACP precision limited by understanding of residual detector asymmetries. First Run II CP Asymmetries! Charm and Beauty at the Tevatron

  22. ≤ 2.4 x 10-6 at 90% CL Flavor Changing Neutral Currents • Look for FCNC in the decay D0mm. • SM prediction ~10-13. • R SUSY effects can raise to ~10-6. • Normalize to D0nts to cancel out various normalizations and reduce detector acceptance effects. • Blinded analysis. Optimize cuts on pp sample. • Able to push current limit downward by ~2. ( PDG 90%CL: < 4.1 x 10-6 ) Charm and Beauty at the Tevatron

  23. D0 Flavor Tagging Status Tagging power :eD2 Significance of a mixing measurement proportional to eD2 e: efficiency for a tag = D: Dilution = Jet tag Muon tag Signal region Sidebands eD2 for signal Charm and Beauty at the Tevatron

  24. Conclusions • Substantially improved trigger and detector. • Some results already pushing the values in the PDG. • Masses, lifetimes, branching fractions • Measurements of Bs, Bc mesons and b-baryons properties available only at Tevatron. • Extensive charm physics reach using two track trigger. • Large samples of fully reconstructed B hadrons to hadronic final states. • Establishing firm basis for exploring CP violation in many areas, especially using the Bs. Charm and Beauty at the Tevatron

  25. Cross Sections and Branching Ratios • During Run I we measured b inclusive cross sections. • These were systematically above the NLO predictions (by factor ~2.5). • Many measurements of cross sections and branching ratios were calculated with respect to a reference signal to avoid uncertainties on trigger efficiencies and measured luminosity. • In this sense, the ‘B factories’ provide us with valuable ‘calibrations’ for our reference signals. Charm and Beauty at the Tevatron

  26. Exclusive B Lifetimes B+gJ/y K+ B0gJ/y K0* (K0* g K+p-) Bsg J/yf (fgK+K-) Simultaneous fitting of MB, ct. ct = LB / pBx MBPDG Charm and Beauty at the Tevatron

  27. Preparing for sin2b • Can measure sin2b with comparable precision to B factories. • Use comparison with B factories to check our analysis techniques. • Working on establishing gold plated mode, BdJ/yKs, reconstruction. Charm and Beauty at the Tevatron

  28. Muons Calorimeters Tracking CDF Run II Detector • Tracking • Silicon Vertex Detector • L00 • Intermediate Silicon • Central Outer Tracker • Endplug Calorimeter • Muon systems • TOF Charm and Beauty at the Tevatron

  29. D0 Run II Detector Build on existing strengths • Excellent calorimetry with faster readout • Upgraded muon system for better m-ID Add new capabilities • Inner tracking (silicon tracker, fiber tracker) with 2T superconducting solenoid • Si Track Trigger (displaced vertices) Charm and Beauty at the Tevatron

  30. 100. 10. Average Number of Interactions per crossing 6 Bunches 1.0 36 bunches 108 bunches 0.1 1031 1032 1033 1030 Luminosity Accelerator Upgrades • Replace Main Ring with Main Injector • Upgrade Pbar storage • Tevatron upgrade: • major luminosity increase • 1031 5 x 1031  2 x 1032 110pb-1 2fb-1  15fb-1 • Short interbunch to limit Nint/crossing • 3.5 ms  396 ns  132 ns Run IRun IIa Run IIb Charm and Beauty at the Tevatron

  31. Run II Improvements • Silicon detectors (SVXII, ISL): • Double SVX length for full acceptance (SVX II) • Double sided silicon for 3-D track reconstruction (SVXII) • More silicon layers & forward silicon (ISL) for standalone tracking • Secondary vertex trigger at LV2 (20 ms) (SVT) • Central tracker (COT): • Double the number of stereo layers (COT) • x 6 more sense wires improves occupancy (COT) • Muon system: • Improved coverage: old “holes” fixed and push to |h| = 1.5 (IMU) • New Plug calorimeter • Add preshower and shower max detector Charm and Beauty at the Tevatron

  32. Dominant Subdominant u W- d W- b b u d u W- s W- b s b u Unitarity Angles g, a • Measure/limit a based on Bdp+p- • Measure g using combination of • Bdp+p- • BsK+K- • Challenges • Separation of Bd,s pp, pK, KK • Understanding penguin contributions (using both decays helps) • In addition there are interference amplitudes due to mixing. • However ample statistics for precision observation of asymmetry. Decays related by d,s interchange Fleischer PLB 459 (1999) 306 Charm and Beauty at the Tevatron

  33. CDF Run II Trigger System Hardware tracking for pT1.5 GeV • Front-end electronics • Level1 Trigger • synchronous, 132 ns • 42 deep pipeline gives 5.5 ms for L1 decision • Accept rate 40-50 kHz • Level2 Trigger • asynchronous • Accept rate 300 Hz • Level3 Trigger (not shown) • Farm of 175 PC’s • Accept rate 75 Hz Detector Muon-track matching L1 trigger Electron-track matching Missing ET, sum-ET Silicon tracking L2 trigger Jet finding Refined electron/photon finding L3 farm Full event reconstruction tape Charm and Beauty at the Tevatron

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