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Exploring Bs Meson Physics at the Tevatron

Delve into Bs meson properties at the Tevatron collider, covering lifetimes, oscillations, CP violation, and hints of new physics beyond the Standard Model. Discover the mysteries of the Bs meson and its implications for physics. 8 Relevant

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Exploring Bs Meson Physics at the Tevatron

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  1. B Physics at the Tevatron Primarily in this talk: Physics of the Bs Meson Matthew Herndon, University of Wisconsin Madison 10-25 years of DØ(Tevatron) France

  2. Physics of the Bs Meson • Introduction • The Bs Meson • More Bs Mesons • Lifetimes and  • Direct CP Violation • Bs Oscillations • CP Violation in BsJ/ • Conclusions

  3. If Not the SM What? Standard Model fails to answer many fundamental questions Look for new physics that could explain these mysteries Look at weak processes which have often been the most unusual: B Physics! • Gravity not a part of the SM • What is the very high energy behaviour? • At the beginning of the universe? • Grand unification of forces? • Dark Matter? • Astronomical observations of indicate that there is more matter than we see • Where is the Antimatter? • Why is the observed universe mostly matter? • Standard Model predictions validated to high precision, however

  4. Bs Mesons s d b b Z' very fast Many new physics possibilities! 79 GHz • Very interesting right from the start. • The Bs known about since UA1 experiment in 1987. • Could infer the existence of a very fast oscillating meson • SS vs OS leptons • New physics and the Bs Meson • One example: Higgs couples to mass, heavier mesons of interest • Investigate • Spectroscopy • Rare Decays • Lifetime and  • Oscillations • CP Violation

  5. The Tevatron Run 2 Bs physics benefits from more data • 1.96TeV pp collider • Excellent performance and improving each year • Record peak luminosity in 2008: 3.2x1032sec-1cm-2 • Run 1 worth of data every few weeks • CDF/DØ Integrated Luminosity • ~5fb-1 integrated, 3fb-1 analyzed • All critical systems operating including silicon • Added ~2fb-1 in 2008

  6. CDF and DØ Detectors EXCELLENT TRACKING: EFFICIENCY EXCELLENT TRACKING: MASS RESOLUTION EXCELLENT TRACKING: TIME RESOLUTION • CDF Tracker • Silicon |η|<2, 90cm long, rL00 =1.3 - 1.6cm • 96 layer drift chamber 44 to 132cm • Triggered Muons and SVT: |η|<1.0 • DØ Tracker • Silicon and Scintillating Fiber • Tracking to |η|<2 • New L0 on beam pipe • Triggered Muon coverage: |η|<2.0

  7. The Triggers Billions of B and Charm Events on Tape TRIGGERS ARE CRITICAL • Hadron collider: Large production rates • σ(pp → bX, |y| < 1.0, pT(B) > 6.0GeV/c) = ~30μb, ~10μb • Backgrounds: > 3 orders of magnitude higher: ~100 mb • Single and double muon based triggers and displaced track triggers

  8. Orbitally Excited Bs** > 5s significance Bs1 36.4  9.0 Bs2* 94.8  23.4 m(Bs1) 5821.4  0.2  0.6 MeV/c2 m(Bs2*)-m(Bs1) 10.20  0.44  0.35 MeV/c2 • Excited Bs states • B+ sample selected using NN • 58,000 Events, then add Kaons • Masses • Other Tevatron discoveries:Bc(CDF,DØ), b(CDF), b(CDF,DØ), b(DØ)

  9. Bs Lifetime and  Many Orthogonal Methods! • Bs Width-lifetime difference between eigenstantes • Bs,Short,LightCP evenBs,Long,HeavyCP odd (without CP violation) • New physics can contribute in penguin diagrams • Measurements • Lifetimes in flavor specific modes: Bs→ Ds, Bs→ Dsl • Lifetime in CP even states: Bs K+ K-, Bs→ Ds(*)Ds(*) • May account for most of the width difference • Measure both lifetimes in BsJ/ • Separate CP states with angular distributions and measure lifetimes • Look for CP Violation

  10. Bs Lifetime Dominated by Tevatron Measurements • Lifetimes in flavor specific modes: Bs→ Ds, Bs→ Dsl • Equal mix of Bs,Short,LightandBs,Long,Heavyat t=0 • Measures:

  11.  Bs CP Even States Contributes to / • CDF: Bs K+ K- • (Bs→ K+K-)=1.53±0.18 ± 0.02 ps • / > -0.08  0.23  0.03 • Shorter than flavor specific • CDF: Bs→ DsDs • / > 2BR(Bs→ Ds(*)Ds(*)) > 0.012(95%CL) • DØ: Bs→ Ds(*)Ds(*) • Inclusive rate accounts for most of  • / > 0.088  0.033  0.036 • Lifetimes in CP specific, even, modes: Bs K+ K-,Bs→ Ds(*)Ds(*)

  12. Bs: BsJ/ CP Violation will change this picture • Directly measure lifetimes in BsJ/ • Separate CP states by angular distribution and measure lifetimes • A0 = S + D wave  P even • A|| = S + D wave  P even • A = P wave  P odd • Bs,Short,Light CP even • Bs,Long,Heavy CP odd

  13. Bs Results: BsJ/ Next CP Violation CDF: Bs = 0.02  0.05  0.01 ps-1 DØ: Bs = 0.085  0.075  0.006 ps-1 • Putting all the measurements together • Fall 07, new results ~20% better • Assuming no CP violation

  14. Bshh: Direct CP Violation First Observations • Direct CP violation expected to be large in some Bs decays • Some theoretical errors cancel out in B0, Bs CP violation ratios • Challenging because best direct CP violation modes, two body decays, have overlapping contributions from all the neutral B hadrons • Separation: mass, momentum imbalance, and dE/dx

  15. Bshh: Direct CP Violation BR(Bs  K) = (5.0  0.75  1.0) x 10-6 • Good agreement with recent prediction • ACP expected to be 0.37 in the SM • Ratio expected to be 1 in the SM • New physics possibilities can be probed by the ratio Lipkin,Phys.Lett. B621 (2005) 126

  16. Bs Mixing: Overview - • Measurement of the rate of conversion from matter to antimatter: Bs Bs • Determine b meson flavor at production, how long it lived, and flavor at decay to see if it changed! tag Bs p(t)=(1 ± D cos mst)

  17. Bs Mixing: CDF/DØ Results March 2005 April 2006: Use 1fb-1 Data Add PID and NNs Nov 2005: Add Ds-3 and lower momentum Ds-l+ March 2006: Add L00 and SST

  18. Bs Mixing: CDF Results A >5 Observation! Can we see the oscillation? 2.8THz

  19. Bs Mixing: DØ Results 3 Evidence • Observed and confirmed at the Tevatron • Now calibration data rather than a physics measurement for LHCb • Interesting to look at LHCb physics prospects talks and see what else we can do at the Tevatron!

  20. Bs Mixing: CKM Triangle ms = 17.77  0.10 (stat)  0.07 (syst) ps-1 |Vtd| / |Vts| = 0.2060  0.0007 (stat + syst)  0.0075 (lat. QCD) Tevatron

  21. BsDsX: CP Violation Most Precise assl Measurement, statistics limited assl = -0.0024  0.0117  0.0020 • CP violation in BsDsX decays • Time dependent, flavor tagged measurement • Uses known Bs oscillation rate • Now possible due to excellent oscillation results • Key issue: understanding background • Detector effects, light B, and DsX • DØ has excellent control of detector effects from ability to reverse the magnetic fields

  22. Bs and CPV in BsJ/ Often called the sin2s analysis • Natural next step once Bs oscillations established • Sensitivity for s in tagged and untagged analysis

  23. CPV in BsJ/ Comb: 0.031 2.2 CDF: 0.07, 1.8 Favoured with all constraints D0: p value 0.085 1.7 from SM CDF: 0.10, 1.5 • Likelihood fit , s plane • Uses time independent and time dependent tagged information.

  24. What Else? • Consider B factory sin2 in charmonium vs. s penguin decays • ccs vs css: Polarization and 2s • Equivalent test is BsJ/(css) vs. Bs (sss) 280 events 3 fb-1

  25. Bs Physics Conclusion Study of the Bs meson has entered the precision era ACP(Bs  K) = 0.39  0.15  0.08 > 2.2 ms = 17.77  0.10 (stat)  0.07 (syst) ps-1 • Tevatron making large gains in our understanding of Bs Physics • Concentrating on areas where there might be hints of new physics • Precision measurement of ms • On the hunt for direct CP violation • Discrepancy in CP violating phase in BsJ/ • Experiments cooperating to produce definitive B physics measurements One of the primary goals of the Tevatron accomplished!

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