1 / 14

Status of B 0 g a 1 p Analysis

Status of B 0 g a 1 p Analysis. ICPV meeting A.Kibayashi H.Ishino March 8, 2007. Introduction. B 0 →a 1 ± p ∓ decays are sensitive to f 2 BaBar has already measured the B.R. and tCPV parameters PRL 97, 051802 (2006) observation of a1pi signal B.R. = (33.2+-3.8+-3.0) x 10 -6

palila
Download Presentation

Status of B 0 g a 1 p Analysis

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. Status of B0ga1p Analysis ICPV meeting A.Kibayashi H.Ishino March 8, 2007

  2. Introduction • B0→a1±p∓ decays are sensitive to f2 • BaBar has already measured the B.R. and tCPV parameters • PRL 97, 051802 (2006) • observation of a1pi signal • B.R. = (33.2+-3.8+-3.0) x 10-6 • hep-ex/0612050 • tCPV analysis • effective f2 (NOT f2!) is measured.

  3. Event selection of B0→a1±p∓, a1±→p±p±p∓ • dr<0.1cm, |dz| < 4cm • eid<0.9, kid<0.4 • flavor tagging and vertexing • 2.2<pbach<2.7 GeV/c • 0.6 < M(a1)< 1.8GeV/c2 • 0.55< M(p+p−) <1.15 GeV/c2 at least one combination of the three pions from the a1 decay • |Dt|<70ps • Charm vetos • 1.86 < M(K−p+p+)<1.88 GeV/c2 for D+p− decays • 3.05< M(p+p−)<3.15 GeV/c2 for J/y K*0 decays • 2.00< M(K−p+p+)<2.05 GeV/c2 for D*+p- decays • |DE|<0.12 GeV, Mbc>5.20 GeV/c2

  4. Analysis procedure • the signal yields from a 3D fit to DE, Mbc and helicity angle distribution. • the helicity angle for discriminating a1p and a2p. • helicity angle definition: the angle between the normal of the a1 decay plane and B direction in the a1 rest frame. • fit parameters: yields of signal, a2p, charm and charmless B decays, continuum, and the DE and Mbc shape parameters of the continuum. a1->3pions L=1 assuming s-wave decay: prim. pion q B

  5. Fitting Results Generic Rare Continuum a1p TM a1p SCF a2pTM a2p SCF

  6. Signal Yield

  7. Branching Fraction Exp7-49 Na1p = 653.43 + 70.55 - 69.15 N(BB) = 534.586  7.044 e = 9.06% (no. falls into our analysis region/no. signal MC generated) Brsub = 0.5, assume 1/2 a1 decay to r0p+, 1/2 r+p0 ePID = 0.906  0.009 (stat)  0.008(syst), for 4 pion final state

  8. Use full recon sample(Exp7-43) Cut -0.15 < DE < -0.05 GeV, Mbc>5.27 GeV/c2 Efficiency from MC = 3.3% B.R. = (2.42  0.05) x10-4 PDG (2.54  0.28) x10-4 Check with B0gD-p+, D-gK+p-p-

  9. Systematic Errorsnot completed yet Need a1 mass fit take e(before lr cut)/e(after lr cut)

  10. Sys. error : Fit Bias GeantMC: from linear fit Sig. in = 653.4 Sig. expected = 628.8 error = 3.8 % ToyMC: Sig. in = 604.7 Sig. out = 604.2 error = 0.1 % total. 3.8 %

  11. Sys. error : dwave • TM helicities differ swave dwave

  12. Sys. error : dwave cont'd • scf DE-Mbc shapes differ dwave swave

  13. Sys. error : dwave cont'd Replace: 1. scf fraction 0.199 g 0.155 (from sig. MC) 2. scf DE-Mbc PDF swave g dwave 3. scf helicity PDF swave g dwave 4. tm helicity PDF swave g dwave => new sig. yield 653.4 g 579.5, 11.3%! Replace one by one... 1. +7.0% 2. -0.1% 3. -0.3% 4. +7.2%

  14. Summery • 50 % BN circulated to the referees • + validity check, sys. error, a1mass fit(?), early next week.

More Related