First Flavor-Tagged Determination of Bounds on CP Violation in Bs &rarr J/&psi &phi Decays

This webpage summarizes the blessed results for the first flavor-tagged determination of bounds on CP violation in a sample of ~2000 Bs &rarr J/&psi &phi decays corresponding to 1.35 fb-1 data.
See also the results on the Lifetime difference and CP violating phase in Bs &rarr J/&psi &phi decays

Details on this analysis can be found in arXiv:0712.2397 submitted to PRL.
Copy of Wine & Cheese talk by Karen Gibson as well as Video of Wine & Cheese talk.


Information on how to include this result for a Combination in Global Fits

We use a Feldman-Cousins technique to determine 68% CL and 95% CL regions in the &betas-&Delta&Gamma plane:


Assuming the standard model predictions of 2&betas and delta_gamma, the probability of a deviation as large as the level of the observed data is 15%, corresponding to 1.5 Gaussian standard deviations.

Additionally, we present a Feldman-Cousins confidence interval of 2&betas, where &Delta&Gamma is treated as a nuisance parameter, and find that 2&betas is within [0.32, 2.82] at the 68% CL.

We also exploit current experimental and theoretical information to extract tighter Feldman-Cousins bounds on the CP-violating phase. By applying the constraint |&Gamma12| = 0.048 +/- 0.018 in the relation &Delta&Gamma = 2|&Gamma12|*cos(2&betas), we restrict &betas in [0.24,1.36] U [1.78, 2.90] at the 68% CL.
If we additionally constrain the strong phases &deltaparalel and &deltaperp to the results from B0 &rarr J/&psi K*0 decays and the Bs mean width to the world average Bd width, we find &betas in [0.40, 1.20] at 68% CL

Below are all figures meant for download.