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“sin2 f 1 ” measurement with b s penguin decays at Belle

“sin2 f 1 ” measurement with b s penguin decays at Belle. Koji Hara (Nagoya University) for the Belle Collaboration. Introduction Measurement of time-dependent CP violation (tCPV) in B 0  h ’ K 0 tCPV result for B 0  K S p 0. b→ccs tree. _. b→sqq penguin. _. _. c. b. b. c. w.

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“sin2 f 1 ” measurement with b s penguin decays at Belle

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  1. “sin2f1”measurement with bs penguin decays at Belle Koji Hara (Nagoya University) for the Belle Collaboration

  2. Introduction • Measurement of time-dependent CP violation (tCPV) in B0h’K0 • tCPV result for B0KSp0

  3. b→ccs tree _ b→sqq penguin _ _ c b b c w _ s d d d Introduction tCPV measurements in B0 decays _ w J/ s η’,φ… B0 t g B0 s _ s K0 K0 d Check if / S=sin21, A ~ 0 “sin21” ≡-ξfS= sin21, A ~ 0 Extra CPV phase “sin2φ1“≠sin2φ1 Hint of New Physics SM Anchor

  4. 2 2 P mode CP P P’ T T’ Ks 1     4 KsKsKs +1     P’ K+KKs     ~+1 Ks      T f0Ks      Ks      4 Ks      T’ SM Contamination • It is essential to estimate possible deviation from sin2f1within the SM to claim new physics. • bu Tree contamination • Final state rescattering color-allowed color-suppresed _ sdd penguin _ sss penguin

  5. Theoretical Estimation • h’K0, fK0, KSKSKS are the “Golden modes” with the smallest expected difference from sin2f1 in SM • Expected differences are mostly positive. For example, [Chua, talk at FPCP06, hep-ph/0605301]

  6. NewtCPV result for B0h’KS+h’KL

  7. signal Bkg Likelihood Ratio (Spherical) (Jet-like) Event Shape Event Selection • Dominant Background is e+e-  qq continuum  Distinguished from signal by the Likelihood Ratio made with event shape variables.

  8. B0h’KS Signal • Event-by-event signal fractions extracted from 3D Mbc-DE-LR fit. LR0.5 LR<0.5 LR h’ rg Ks(p+p-) 794  36  h(2g)pp Ks(p+p-) 363  21  h(3p)pp Ks(p+p-) 100  11 rg Ks(p0p0) 103  15 h(2g)pp Ks(p0p0) 62  9 Total1421 46

  9. B0h’KL Signal • Signals are extracted from PB*-LR 2D fit Background subtracted h’h(2g)pp KL 392  37 h(3p)pp KL 62  13 Total 454  39 LR PB*(GeV/c)

  10. B0h’K0 Result Background subtracted • Consistent with sin2f1 • 5.6s First observation of tCPV in bsqq penguin “sin2f1”=+0.64 0.10 0.04 A=- 0.010.07  0.05 good tag

  11. CP Fit Results for B0h’KS, KL h’KS Background subtracted “sin2f1” good tag h’KL Background subtracted good tag A errors are statistical only

  12. NewtCPV result for B0KSp0

  13. tCPV in KSp0 • bs penguin dominant mode S sin2f1 (Possible deviation within SM ~O(0.1) ) • A Member of Kp Family A is important to check the sum rule A(K+p-)+A(K0p+)=A(K+p0)+A(K0p0) • No primary tracks from B vertex • Vertex reconstruction with KS trajectory [Gronau, Phys. Lett. B627, 82 (2005)]

  14. B0KSp0 Signal Signal yield: 515  32 LR<0.7 LR0.7

  15. Vertex Reconstruction with KS Ks track p+ p- • Extrapolate KS track to the Interaction Point • Vertex reconstruction efficiency ~33% • Events without the vertex can still be used for A measurement. IP profile BCP vertex • The validity is confirmed with the J/yKS as control sample. • B0 Lifetime 1.503+/-0.036 ps • sin2f1=+0.68+/-0.06 J/yKS with the KS Vertexing Raw asymmetry good tag

  16. B0KSp0 tCPV Result Consistent with • sin2f1 from bc • the sum rule expectation A = -0.150.06 using Belle 532M A, Br and PDG2006 t+/t0 “sin2f1”=+0.33 0.35 0.08 A=- 0.050.14  0.05 good tag

  17. Summary • tCPV in bsqq modes are sensitive to the new physics • “Golden modes” are fK0, h’K0, KSKSKS • New Results from Belle with 532 M BB • Other tCPV results will be reported in the Plenary Talk by M. Hazumi. B0h’K0 “sin2f1”=+0.64 0.10 0.04 A=- 0.01 0.07 0.05 5.6s tCPV observation B0KSp0 “sin2f1”=+0.33  0.35  0.08 A=- 0.05  0.14  0.05

  18. B0h’KS DE distribution

  19. B0h’KS,h’KL Results “sin2f1”=+0.67 0.11 A=- 0.030.07 “sin2f1”=+0.46 0.24 A=+ 0.090.16 errors are statistical only

  20. “sin2f1” A

  21. Systematic Errors h’K0 KSp0 dS dA dS dA Vertexing 0.013 0.021 0.011 0.020 Flavor tagging 0.004 0.007 0.008 0.005 Resolution 0.035 0.024 0.066 0.010 Physics 0.001 0.007 0.007 0.001 Possible Fit bias 0.007 0.005 0.009 0.004 BG fraction 0.020 0.022 0.009 0.001 BG dt shape 0.004 0.002 0.046 0.019 Tag-side interference 0.001 0.024 0.001 0.043 ---------------------------------------------- Total 0.043 0.047 0.082 0.053

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