Bs mixing and CPV at D0 & ATLAS B physics future

1. Bs mixing and CPV at D0 & ATLAS B physics future Eduard De La Cruz Burelo CINVESTAV Flavor physics: The mexican taste

2. Outline: • What are we doing in D0 on B Physics? • What are the plans for B physics in ATLAS? http://www-d0.fnal.gov/Run2Physics/WWW/results/b.htm Flavor physics: The mexican taste

3. The B hadron family Flavor physics: The mexican taste

4. The useful Bs • QCD modeling: compare & contrast with Bd • SU(3) Flavor Symmetry, Heavy Quark Effective Theory • Lattice … • Direct search for beyond de SM effects • Rare (leptonic) decays: many models predict large effects in Bs. • EW symmetry breaking • In SM: EW sym. breaking ↔ Flavor struct. (CKM, CPV) • 1 SM Higgs doublet  strong flavor constraints • FCNCs suppressed Unitary VCKM • 1 param. for all CPV No CPV in flavor diag. processes • Other model much less constrained • eg. 43 CPV parameters in MSSM • Different relationships b/w observables from different families Flavor physics: The mexican taste

5. Mixing and CP violation Flavor physics: The mexican taste

6. D0/CDF battle • Bs mixing • CP violation in BsJ+ Small CPV phase in Bs→J/yf Bd sides ≈ Vub/Vtd ≈ 1 Bs sides ≈ Vub/Vts ≈1/20 Im CKM axis Real CKM axis Large CPV phase in Bd→J/y KS Flavor physics: The mexican taste

7. Bs mixing phenomenology • Mixing or oscillation: Particle ↔ antiparticle transitions via second order weak interaction. • Mass eigenstates a mixture of flavor states: • Probability of unmixed and mixed decays: Flavor physics: The mexican taste

8. Flavor tagging methods: OST & SSKT Flavor physics: The mexican taste

9. Data Flavor physics: The mexican taste

10. Amplitude scan: Flavor physics: The mexican taste

11. Likelihood scan Flavor physics: The mexican taste

12. Oscillation frequency ms s plane ms |s|/ms asfs Flavor physics: The mexican taste

13. BsJ+ : CP violation via Bs mixing Flavor physics: The mexican taste

14. CP violation in BsJ+ • BsJ+ combines many aspects • vector + vector final state so it has both CP-even and CP-odd components. • Measurable lifetime difference so you can tell the difference between BsLong and BsShort • CP eigenstate so accessible to both Bs and Bs bar, interference with decay before or after mixing Flavor physics: The mexican taste

15. CP violation in BsJ+ We can use angular distribution of decay products to separate CP-even and CP-odd components. And flavor tagging algorithms can we used to know the original flavor. Flavor physics: The mexican taste

16. Lifetime analysis J/y + f polarization Bs decay length even component BsLong component odd component BsShort component Flavor physics: The mexican taste

17. CP violation in BsJ+ Strong phases constrained Flavor physics: The mexican taste

18. CDF+D0 combined results Without constraints in strong phases Flavor physics: The mexican taste

19. Where do we go now? • s from BsDs(*)Ds(*) (purely CP even) Flavor physics: The mexican taste

20. s from BsDs(*)Ds(*) Flavor physics: The mexican taste

21. B Physics in ATLAS Integrated luminosity Rare decays 100 fb–1 Production and decay properties of B-hadrons 10 fb–1 1 fb–1 B-hadron properties, new decay limits Understand backgrounds for rare decays 100 pb–1 Test beams, Cosmic runs, Pre-alignment and calibration, Data distribution dress rehearsals Initial detector and trigger synchronisation and commis-sioning, calibration & alignment, material mapping, … Measuring production cross section 10 pb–1 Time LHC startup Flavor physics: The mexican taste

22. Semi-rare decays • b → s(d)l+l- FCNC transitions in SM • forbidden at the tree level, at lowest order occur through 1-loop penguin and box diagrams • branching ratio ~ 10-6- 10-7 • They provide a good test of the SM and indirect search for signals of physics beyond the SM • measure values of |Vts| and |Vtd| CKM matrix • differential decay rate sensitive to new physics • forward-backward asymmetry • dilepton invariant mass spectrum • provide information on long-distance QCD effects Flavor physics: The mexican taste

23. b  d,s +- @ 30fb-1 • B  K0* mm • SM • non-SM Flavor physics: The mexican taste

24. Rare decays Current Tevatron limit • Very rare decay Bs→: SM - BR (Bs →) = (3.4 0.4)10-9 • Current limits (2fb-1): • CDF note 8956 BR (Bs →) < 5.8  10-8 95% CL • D0 note 5344-CONF BR (Bs →) < 7.5  10-8 90% CL BR (Bs →) may be enhanced by several order of magnitudes due to new loop diagrams • Anomalous magnetic moment of the  • Muon g – 2 collab. measurement deviates by 2.7 from SM: a = (25.29.2)10–10 • Implications on Bs  +– within constrained MSSM: • 250 < m1/2(gaugino mass) < 650 GeV  BR (Bs  ) = 510 –9 – 10–7 The CMSSM prediction for BR (Bs → μ+μ−) hep-ph/0411216 Flavor physics: The mexican taste

25. Bs+- @ ATLAS • With 2 fb-1 BR<(0.7-2)10-8 • With 10 – 30 fb-1 SM prediction region • 3 years 1033 cm-2s-1 3σ evidence • First year 1034 cm-2s-1 5σ evidence Flavor physics: The mexican taste