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Heavy Flavor Physics at Tevatron Run II

Heavy Flavor Physics at Tevatron Run II. Kin Yip. Introduction (Collider and Detector Upgrade) Detector Performance First results ( lifetimes, masses , … ) Summary First International Workshop on Frontier Science: Charm, Beauty and CP Frascati, Oct. 10 th , 2002. Fermilab. CDF.

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Heavy Flavor Physics at Tevatron Run II

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  1. Heavy Flavor Physics at Tevatron Run II Kin Yip • Introduction (Collider and Detector Upgrade) • Detector Performance • First results (lifetimes, masses, … ) • Summary • First International Workshop on Frontier Science: Charm, Beauty and CP • Frascati, Oct. 10th, 2002

  2. Fermilab CDF • collisions • Ecom = 1.96 TeV • 396 ns bunch spacing • Run II peak luminosity •  now: 3.21031 cm-2s-1 •  goal: 8.61031 cm-2s-1 source DØ Chicago  CDF Booster p Tevatron p Main Injector & Recycler Run IIa

  3. Integrated Luminosities • Tevatron: Center of Mass Energy = 1.96 TeV • Expect 2 fb1by end of 2004 (Run IIa), 15 fb1 by 2008 (Run IIb) CDF

  4. Hadron colliders challenge • Large production cross section • Even larger inelastic cross section (S/B10-3)  specialized triggers: • Single lepton triggers • Dilepton triggers such as J/ +  - • Track triggers moved to L1 (RunII) • In Run II, L2 trigger on displaced tracks using SVX will allow CDF to trigger purely hadronic B decays and study such as B0 +, Bs Ds+ ... • Precise 2nd vertex reconstruction at 2 TeV at Z0 at (4S)

  5. CDF Detector Run II Upgrades All critical components are working well 132 ns front end COT tracks @L1 SVX tracks @L2 40000/300/70 Hz ~no dead time 7-8 silicon layers rf, rz, stereo views z0max=45, max=2 2<R<30cm 2 b’s or not 2 b’s? Double tags essential for Mtop, Hbb TOF (100ps@150cm) 30240 chnl, 96 layer drift chamber s(1/pT) ~ 0.1%/GeV s(hit) ~ 150mm  coverage extended to =1.5 Tile/fiber endcap calorimeter (faster, larger Fsamp, no gap)

  6. The Upgraded D Detector SMT SMT SMT • Added PreShower detectors, Central (CPS) and Forward (FPS) • Significantly improved Muon System • New forward proton spectrometer (FPD) • Entirely new Trigger System and DAQ to handle higher event rate • New tracking devices, Silicon (SMT) and Fiber Tracker (CFT), placed in 2 T magnetic field • Upgraded Calorimeter electronics readout and trigger

  7. CDF and DØ in Run II • Stable physics running established in early 2002 • CDF: • Silicon coverage, trigger came together quickly • CDF: L1/L2/L3 trigger 6400/145/25Hz @21031, 1% deadtime (BW 40K/300/70) • ~140 trigger algorithms increased rapidly in sophistication; now quite stable • DØ: • New detectors such as Silicon and Fiber Trackers have worked well: •  95% of the SMT and  98% CFT channels are available for readout • Triggers have come together gradually: L1/L2/L3 trigger 400/150/50Hz @21031 • Results shown here are from data recorded ~January-early summer 2002 • Mostly using data of 10.0 pb1 ( passing some stringent “good run” criteria ) for both experiments • Especially for CDF, already in the mode of very stable operation and collecting publication-quality data

  8. Tracking (SMT/CFT) Performance track x pT (GeV) y Impact Parameter (DCA) Resolution • Almost on target with • no CFT alignment • 1st pass SMT alignment DCA Secondary Vertices DØ Run 2 Preliminary KS+- width = 36 m (beam) = 30 m   = 20 m mass +- Improvement expected from alignment with data in near future …

  9. Muon System Performance Muon Timing ’s from Collisions Cosmic rays Timing cuts reduce cosmic bckg., could aid in detection of slow moving particles Matching of central tracks to ’s improves momentum resolution shielding J/ invariant mass Muon stand alone system Muon plus central tracking M = 3.08  0.04 GeV  = 0.78  0.08 GeV

  10. Hadronic B trigger (revolutionary!) ~150 VME boards find & fit silicon tracks, with offline accuracy, in a 15 ms pipeline Online track impact param. s=48 mm includes ~33 mm beamspot The wisest are the most annoyed by the loss of time. -Dante • CDF: Secondary Vertex L2 Trigger • Impact Parameter resolution as planned • 48 mm (33 mm beam spot transverse size) • Rf only  need beamline || silicon • Dis implementing the displaced track L2 trigger and should be online in the New Year >90% Efficiency soon 80%

  11. B Physics Cross-sections Data PYTHIA • New tracking in 2 Tesla field • Muon triggers up to ||< 2 • J/ Cross Section Measurement • Luminosity ~5 pb-1 • First measurement in this rapidity region and ECM jet • b-quark Production Cross Section • New ECM • Luminosity ~5 pb-1 • Jet || < 0.6 • muon tag only, b-content from pTrel fits

  12. B hadron lifetimes • Inclusive B lifetime with J/y’s Fit pseudo-ct = Lxyy*FMC*My/pTyct=458±10stat. ±11syst.mm (PDG: 469±4 mm) • Exclusive B+J/yK+lifetime ct=446 ±43stat. ±13syst.mm (PDG: 502±5 mm) • J/y from B = 17% # B ~ 154

  13. B Lifetime Measurement • B lifetime measurement from inclusive J/ • 416 ± 30 signal events • 2184 ± 47 prompt J/’s • (B) = 492 ± 37 m (stat. error) (PDG: (B) = 469 m) • Exclusive B reconstruction • B±J/ K± • First time in DØ • Expect more soon! ~5 pb-1 • pT(B)>10 GeV/c

  14. SVT selects huge charm signals! • L2 trigger on 2 tracks: • pt > 2 GeV • |D| > 100 mm (2 body) • |D| > 120 mm (multibody) • Whopping charm samples! • Will have O( 107 ) fully reconstructed decays in 2/fb data set • FOCUS = today’s standard for huge: 139K D0K-p+, 110K D+K-p+p+ • A substantial fraction comes from b decays 56320 D0 25570 D±

  15. Meson mass measurements • B masses: • y(2S)J/y p+p- (control) • Bu J/y K+ • Bd J/y K0* (K0*K+p-) • Bs J/y f (fK+K-) 18.4/pb BsJ/yf More mass plots CDF 2002DPDG/s y(2S) 3686.43 ±0.54 0.9 Bu 5280.6 ±1.7 ±1.1 0.8 Bd 5279.8 ±1.9 ±1.4 0.2 Bs 5360.3 ±3.8 ± -2.1 BJ/yK 18.4/pb Bu 2.1 2.9

  16. Measure Ds, D+ mass difference • Ds± - D± mass difference • Both D  fp (fKK) • Dm=99.28±0.43±0.27 MeV • PDG: 99.2±0.5 MeV (CLEO2, E691) • Systematics dominated by background modeling 11.6 pb-1 ~2400 events ~1400 events Brand new CDF capability

  17. Measure Cabibbo-suppressed decay rates Already comparable! • G(DKK)/G(DKp) = (11.17±0.48±0.98)% (PDG: 10.83±0.27) • Main systematic (8%): background subtraction (E687, E791, CLEO2) • G(Dpp)/G(DKp) = (3.37±0.20±0.16)% (PDG: 3.76±0.17) • several ~2% systematics • This measurement has pushed the state of the art on modeling SVT sculpting--essential simulation tools for both B physics program and e.g. high-pT b-jet triggers Future? - CP violation - mixing - rare decays Monster Kp reflection here ...

  18. Toward Bs mixing! Next step: • reconstruct Dscandidates in lepton events • Find B0scandidates and measure the proper decay time • Limited proper time resolution due to neutrino K+K- #B± = 56±12 B+ D0p+ • We observe hadronic B decays! • Next steps: • Reconstruct Bs Dsp, Dsfp • Flavor tagging algorithms • Exploit 2SVX acceptance, SVT efficiency improvements

  19. Flavor Oscillations ( BS ) in Run II • Expected signal: 20,000 BsDsp +,Dsp+p+p with Dsf p, K*K  • Flavor tag effitiveness : D2 ~ 11% (with Time of Flight) • Proper time resolution: st = 0.045 ps  t • sPT/PT ( SVXII with L00 ) • Average Significance (how many s’s): • Sensitive to xs<63 if S/B=2/1 • Sensitive to xs<56 if S/B=1/2 ( using Layer 00 + TOF in CDF ) • SM Global fit: 20 < xs< 30.8 @96% C.L.

  20. 2-body hadronic B decays observed!! • Yield lower than expected (now improved); S/N better than expected • With 2 fb1 sample, measuring g to ~10º may be feasible, using Fleischer’s method of relating BsKK and Bdpp, and using b as input —sum BdKp BsKK Bdpp BsKp CDF II simulation Width ~45MeV #B = 33±9 B  h+ h-

  21. 0b Lifetime • Theoretical expectation is • Measurement is • Previous measurements used semileptonic modes to achieve statistical precision • Disadvantage is that neutrino is lost, carrying with it momentum information • Fully hadronic mode 0bJ/ 0 • BR(0bJ/ 0)=5x10-4 • Trigger on J/ +- events, reconstruct 0p • Expect 15 000 events • No need to rely on Monte Carlo for momentum correction From B Lifetime Working Group

  22. 0b Lifetime • 0 p • Highest pT track assigned the proton mass • Veto events where M( ) consistent with Ks0 mass • Next step: search for 0 p candidates in J/ events 0p

  23. Measurement of sin(2) in Run I +0.41 -0.44 sin2=0.79 Float md (stat. + sys.) • The minimization of the likelihood function yields: sin2=0.790.39(stat)0.16(syst) Statistical error >systematics. Time integrated measurement • sin2=0.710.63 (stat  sys) • Using Feldman and Cousing frequentist approach • 0<sin2<1 @93%C.L.

  24. Sin(2b) Expectations for 2 fb1 (from the report “B Physics at the Tevatron: Run II and Beyond”) For a time dependent analysis: • D: • (S/B ~ 0.75) • eD2~ 9.8 % • Time resolution • st ~ 100 fs • assuming luminosity ~ 2 fb1 • D and CDF have similar precisions

  25. Summary • Excellent heavy flavor physics prospects for Run II at Tevatron: • Both experiments have come together finally • Heavy flavor physics is probably the least affected by the luminosity at Tevatron and the broad range of B physics programs include: • Charm Physics (largest sample !) • †flavor oscillations (mS) • CP violation: sin(2b) in B  J/ KS • 0b lifetime, sin(2a), observing decay modes related to , †measuring CP violation in oscillation, … † perhaps currently unique to Hadron Machine

  26. How many Bd may we get ? assuming luminosity ~ 2 fb-1

  27. Muon Triggers PT(B)> 4 GeV and || < 3 DØ GEANT/Trig. Sim. max level 2 rate for all DØ triggers is 1000 Hz

  28. Sin(2b) viaB  J/ + KS + -  + J/ KS  - B b  - b + |Qjet| > 0.2 • full reconstruction of final state • two V’s • soft pions • measure decay length • tag flavor at production • same side flavor tag • pion charge • opposite side flavor tags • lepton charge • jet charge Efficiency (e) and dilution factor (D) D = 2 P - 1 P is the correct tag probability eD2 is the tag’s effectiveness

  29. Flavor Tagging

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