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LHCb performance for B s  J/   and B d  J/  K s decays Jeroen van Hunen

LHCb performance for B s  J/   and B d  J/  K s decays Jeroen van Hunen. B s  J/   and B d  J/  K s. }. B d  J/  K s B s  J/  . CP eigenstate and a mixture of CP-odd and CP-even states. . }. no CPV in decay. If   fcp  0. CP-symmetry. single weak phase.

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LHCb performance for B s  J/   and B d  J/  K s decays Jeroen van Hunen

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  1. LHCb performance for BsJ/ and BdJ/  Ks decays Jeroen van Hunen

  2. BsJ/  and BdJ/  Ks } BdJ/ Ks BsJ/  CP eigenstate and a mixture of CP-odd and CP-even states  } no CPV in decay If  fcp  0 CP-symmetry single weak phase  CP violated (interference mixing and decay) no CPV in mixing Physics at LHC, Prague

  3. CP - Asymmetry CP-eigenstate, |f| = 1 :  = 0 (for B0d) : Physics at LHC, Prague

  4. BsJ/ and BdJ/ Ks   J/ = sin 2s   J/Ks = sin 2 Physics at LHC, Prague

  5.  = 10 MeV +- mass (GeV) J/  +- selection • Two opposite charged muons with : • Pt > 0.5 GeV • Vertex with a 2 < 9 • Invariant mass within 50 MeV/c2 of mJ/ Physics at LHC, Prague

  6. J/  e+e-selection • Two opposite charged electrons one with Pt > 0.8 GeV/c and one with Pt > 1.8GeV/c • A vertex 2 < 6 • vertex |Z| < 150mm • An invariant mass between 2.7 – 3.2 GeV/c2  = 66 MeV e+e- mass (GeV) Physics at LHC, Prague

  7.   K+K- selection • Two opposite charged kaons with Pt > 0.5 GeV, giving a vertex with a 2 < 9, an invariant mass within 20 MeV/c2 of m, and P > 12 GeV/c2 BsJ/   selection • Combine the J/  and  if thefour tracks form a vertex with 2 < 20, then select the primary vertex with smallest IP (< 4mm) Physics at LHC, Prague

  8. BsJ/   selection • Other constraints on the Bs0 : • Proper time (consistency between the Bs0 momentum and the vector between the production and decay vertex) significance > 5 • mBswithin 50 MeV/c2 of the nominal Bs0 mass +-K+K- Mass +-K+K- Mass  residual  = 38 fs  =15MeV bb-incl. Physics at LHC, Prague

  9. Ks +- selection • Two oppositely charged pions, giving a vertex with a z position between 0 - 3 meter, invariant mass within 60 (100 for TT) MeV/c2 of mKs, and a combined Pt >200 MeV/c. Physics at LHC, Prague

  10. BdJ/ (+-)Ks selection Bd : combining J/  and Ks • J/  and Ksmake a vertex with 2 < 50 • IP significance of Kswith respect to J/  vtx < 3.5 (< 8 for TT) • IP significance of Ks pions with respect to the primaryvtx > 4 (2 for TT) • significanceof the distance between primary andJ/  vtx > 1.2(LL), 3.1(LV), 2.4(TT) • Bd mass window 60 MeV/c2 Physics at LHC, Prague

  11. BdJ/  Ks selection Results for the Bd0 mass : =12 MeV =14 MeV =9 MeV LL TT LL J/ (e+e-)Ks (LL) J/ (+-)Ks (TT) J/ (+-) Ks (LL) Physics at LHC, Prague

  12. Annual yield and Background estimatefor BsJ/   and BdJ/  Ks Physics at LHC, Prague

  13. Sensitivity studies for BsJ/   and BdJ/  Ks Physics at LHC, Prague

  14. Extracting s from BsJ/  BsJ/  A = odd & A0,|| = even BsJ/  2s  0.03 in SM : A(t)  two exponentials with lifetimes 1/H and 1/L Physics at LHC, Prague

  15. Extracting s from BsJ/  untagged Bs tagged Bs tagged Extreme CP-Parameters: s=150 s/s = 0.5 0 1 2 3 4 (ps) Physics at LHC, Prague

  16. Sensitivity for s from BsJ/  Angular analysis to determine the sensitivity for: R(A fraction), s , s and s (for ms and wrong tag fraction:fit Ds simultaneously) R = |A|2/(|A0|2 +|A|||2 +|A|2 ) • = 35% &  = 40% Physics at LHC, Prague

  17. Sensitivity for  from BsJ/ Ks • = 35%  = 35% Proper time Physics at LHC, Prague

  18. Conclusions • Reconstruction of BsJ/ and BdJ/  Ks decays : • Good mass (9-15 MeV/c2) & vertex (107-199 m) resolution •  Excellent proper time resolution (38 fs) allows to follow the oscillations of the decay rates accurately. • High annual yields with low background rates •  Precise determination of CKM angles  and s Physics at LHC, Prague

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