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B mixing and lifetimes at the Tevatron

B mixing and lifetimes at the Tevatron. FPCP 2006 Vancouver. Jónatan Piedra LPNHE-University Pierre et Marie Curie / CNRS-IN2P3 on behalf of the D  and CDF Collaborations. Outline. THIS TALK. OTHER TALKS. CDF and D  detectors CDF and D  Hot Topics Detailed B s mixing at D 

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B mixing and lifetimes at the Tevatron

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  1. B mixing and lifetimes at the Tevatron FPCP 2006 Vancouver Jónatan PiedraLPNHE-University Pierre et Marie Curie / CNRS-IN2P3 on behalf of the D and CDF Collaborations

  2. Outline THIS TALK OTHER TALKS • CDF and D detectors • CDF and D Hot Topics • Detailed Bs mixing at D • D. Buchholz • D Hot Topics • Detailed B  hh • D. Tonelli • CDF Hot Topics • Bc lifetime • I. Kravchenko • B Spectroscopy • Bs Ds Ds • R. Van Kooten • Bs Decays and B leptonic decays • Precision B Lifetimes • motivation • Lb • Bs • Bs lifetime difference • B Mixing • current status • ingredients • results • Summary J. Piedra

  3. Precision B Lifetimes

  4. Precision B Lifetimes Motivation C. Tarantino, hep-ph/0310241 THEORY (NLO) EXPERIMENT • b-hadron decays dominated by b-quark • Light quarks are included with 1/mb perturbative expansions (HQE) • expect small differences between lifetimes of different species • lifetime ratios reduce theory uncertainties J. Piedra

  5. Precision B LifetimesLb Lifetime CDF 370 pb-1 D250 pb-1 PRL 94 102001 (2005) • CDF and D have measured Lb J/L lifetime • Better proper time resolution than LbLc ln(world average dominated) • Earlier t(Lb)/t(B0) predictions were 2s above experiment • new calculations including higher order effects predict lower ratio

  6. Precision B LifetimesLb Lifetime at CDF CDF 370 pb-1 HFAG • Analysis based upon 370 pb-1 • Technique • unbinned maximum likelihood fit to proper decay-length and mass • Lb J/L0194  23 candidates • J/mm • L0 pp - • Use B0 reference mode • larger yield and similar decay topology • B0 Jpsi Ks01225  53 candidates • J/mm • Ks0p +p -

  7. Precision B LifetimesBs Lifetime CDF 360 pb-1 D400 pb-1 • D and CDF measure lifetime in best in the world

  8. Precision B Lifetimes Neutral Meson Mixing • Quark mixing  non-diagonal Hamiltonian for • Diagonalizing the Hamiltonian results in • two eigenstates and • two masses mH and mL, with Dm  mH – mL • two decay widths GH and GL, with DGGL– GH R. Van Kooten Bs decays and B leptonic decays

  9. Precision B LifetimesBs Lifetime Difference • Bs J/ • Pseudoscalar  Vector - Vector • Decay amplitude decomposed into 3 linear polarization states • A0 = S + D wave  P even • A|| = S + D wave  P even • A = P wave  P odd • If CP violation neglected • Bs,Light  CP even • Bs,Heavy  CP odd • angular distributions are different • Angular analysis separates CP eigenstates  measure two lifetimes J. Piedra

  10. Precision B LifetimesBs Lifetime Difference CDF 260 pb-1 D800 pb-1

  11. Precision B Lifetimes................... and best in the world CDF 360 pb-1 D210 pb-1 CDF 360 pb-1 • First measurement(~95% CP even) D. Tonelli CDF Hot Topics • Expected • Lifetime extracted from decay I. Kravchenko B Spectroscopy

  12. Precision B Lifetimes HFAG • B+andB0 at LEP/SLC, B factories and Tevatron (CDF/D) • dominated by Belle and BaBar • Bs dominated by Tevatron, LEP • Bc at Tevatron • Lb dominated by LEP, Tevatron

  13. B Mixing

  14. B Mixing Theoretical Prediction CKM fit • SM prediction for the ratio of Bs and B0 mixing frequencies • Dmd precisely measured • Dms not yet measured precisely • Potential NP discovery J. Piedra

  15. B Mixing Significance S signal candidates B background candidates sct time resolution • The dilution D measures the purity, D= 0 (1) random (perfect) tagger • The dilution attenuates the observed oscillations

  16. B Mixing Ingredients Opposite Side Trigger Side

  17. B Mixing Reconstructed...................... D1 fb-1 CDF 1 fb-1 • D exploits semileptonic decays from m trigger • CDF uses both electrons and muons

  18. B Mixing Reconstructed..................... • CDF collects hadronic B decays by triggering on impact parameter • Around 3700 Bs signal candidates J. Piedra

  19. B Mixing Proper Decay Time • Procedure • measure pT of Bdaughter tracks • measure the decay length Lxy • boost B back to its rest frame • Fully reconstructed decays • all daughters reconstructed • Partially reconstructed decays • some tracks escape detection  need simulation J. Piedra

  20. B Mixingb-Flavor Tagging • A flavor tagger determines the b-flavor at production time • bb production  flavor tagging on the Trigger Side or the Opposite Side • Soft Lepton Tagger • look for B  lnDX decay on the OS • lepton charge indicates b-flavor • Jet Charge Tagger • look for jet or secondary vertex from OS • jet charge indicates b-flavor • Same Side (Kaon) Tagger • look for a fragmentation track on the TS • it is charge correlated with the b-flavor SLT Trigger Side JQT Opposite Side SS(K)T J. Piedra

  21. B Mixing Flavor Analysis on B+ and B0 combined eD2 (%) D CDF 2.48  0.22 1.55  0.08 • Calibrate opposite side flavor taggers prior to Dms analysis • combine several B+,0 decays • combine all taggers • Direct Dmd measurement • cross-check for Bs mixing asymmetry D semileptonic 1 fb-1 Dmd= 0.506  0.020 (stat)  0.016 (syst) ps-1 CDF semileptonic 1 fb-1 Dmd= 0.509  0.010 (stat)  0.016 (syst) ps-1 CDF hadronic 355 pb-1 Dmd= 0.536  0.028 (stat)  0.006 (syst) ps-1 world average Dmd= 0.508  0.004 ps-1

  22. B Mixing SSKT at CDF • Look for the fragmentation track that is charge correlated with the B • Dms not yet measured precisely • Parameterization from MC • Extensive data/MC comparisons on all tagging related quantities • Rely on MC prediction of SSKT performance for Bs mixing

  23. B Mixing SSKT at CDF CDF MC 355 pb-1 • Systematic studies cover • quark fragmentation model • bbproduction mechanisms • excited B mesons content • detector / PID resolution • particle species content around B • data / MC agreement • Select track within DR < 0.7 around B most likely to be a kaon • based on dE/dx and TOF information

  24. B Mixing Fourier Analysis frequency domain time domain • Two domains to fit for oscillations • time fit for a cosine wave • frequency examine f-spectrum • Time domain approach • fit for Dms in P(t) ~ 1Dcos(Dmst) • Frequency domain approach • introduce amplitude, P(t) ~ 1ADcos(Dmst) • fit for A at different Dms  obtain frequency spectrum A(Dms) • standard method for combining limits • with flavor taggers calibrated A = 1 for the true Dms else A = 0

  25. B Mixing Amplitude Scans on Dmd D Run II Preliminary • The yellow band is 1.645sA around data points • Dm values where A + 1.645sA < 1 are excluded at 95% CL • Sensitivity is where 1.645sA = 1 1 fb-1 Amplitude scan works on B0 decay modes

  26. B Mixing Amplitude Scans on Dms D1 fb-1 CDF 355 pb-1 95% CL limit 14.8 ps-1 95% CL limit 8.6 ps-1 sensitivity 14.1 ps-1 sensitivity 13.0 ps-1 A/sA(Dms = 19 ps-1) = 2.5 5%p-value SSKT not yet included J. Piedra

  27. B Mixing Log Likelihood Scan hep-ex/0603029 submitted to Phys. Rev. Lett. • 17 < Dms < 21 ps-1 @ 90% CL assuming Gaussian uncertainties

  28. B Mixing D Effect on World Average HFAG preliminary (correlated systematics not included) D • A(Dms = 19 ps-1) • 1.5 sA2.3 sA D

  29. Summary • New Lb lifetimes reduce distance with theory • Tevatron measures the best Bs lifetimes in the world • Bs lifetime difference within SM • DBs oscillation • 1 fb-1 • 2.5 sA excess at Dms = 19 ps-1(5%p-value) • 17.1 < Dms < 21.1 ps-1 @ 90% CL • CDF Bs oscillation • 355 pb-1 • Dms > 8.6 ps -1 @ 95% CL

  30. Backup

  31. Precision B Lifetimes Transversity Basis  • Transversity basis J/ rest frame •  flight direction +x • KK plane xy plane J. Piedra

  32. B Mixing Semileptonic Decay Time • Missing particles  missing pT • Determine pseudo-ct from data • ct = ct* kMC • include kMC effect in signal PDF J. Piedra

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