Abstract:
We present a measurement of the CP-violating parameter βsJ/ψ using approximately 6500 Bs0→J/ψ decays reconstructed with the CDF II detector in a sample of pp̄ collisions at √s=1.96TeV corresponding to 5.2fb -1 integrated luminosity produced by the Tevatron collider at Fermilab. We find the CP-violating phase to be within the range βsJ/ψ [0.02,0.52] [1.08,1.55] at 68% confidence level where the coverage property of the quoted interval is guaranteed using a frequentist statistical analysis. This result is in agreement with the standard model expectation at the level of about one Gaussian standard deviation. We consider the inclusion of a potential S-wave contribution to the Bs0→J/ψK +K - final state which is found to be negligible over the mass interval 1.009<m(K +K -)<1.028GeV/c2. Assuming the standard model prediction for the CP-violating phase βsJ/ψ, we find the Bs0 decay width difference to be ΔΓ s=0.075±0.035(stat) ±0.006(syst)ps -1. We also present the most precise measurements of the Bs0 mean lifetime τ(Bs0)=1.529±0.025(stat) ±0.012(syst)ps, the polarization fractions |A 0(0)|2=0. 524±0.013(stat)±0.015(syst) and |A -(0)|2=0. 231±0.014(stat)±0.015(syst), as well as the strong phase δ -=2.95±0.64(stat)±0.07(syst)rad. In addition, we report an alternative Bayesian analysis that gives results consistent with the frequentist approach. © 2012 American Physical Society.