1 / 18

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.

howard-walton
Télécharger la présentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related