2010/12/05 by Giurgiu, Gavril
Engineering · Physics and Astronomy · #Atomic and Molecular Physics #Atomic and Subatomic Physics Research #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Particle accelerators and beam dynamics
paper · pdf · doi:10.48550/arxiv.1012.0962
openalex publication_date 2010/12/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The CDF collaboration presents an updated measurement of the CP-violating parameter betas and of the decay width difference Delta Gammas using approximately 6500 Bs to J/Psi Phi decays collected by the dimuon trigger and reconstructed in a data sample corresponding to 5.2/fb of integrated luminosity. Besides exploiting the two-fold increase in the data sample with respect to the previous measurement, several improvements have been introduced in the analysis including a fully data-driven flavor tagging calibration and proper treatment of possible S-wave contributions. We find that the CP-violating phase is within the range betas in [0.02, 0.52] U [1.08,1.55] at 68C.L. The Standard Model p-value is 0.31. The decay width difference is found to be Delta Gammas = 0.075 +/- 0.035 (stat) +/- 0.01 syst 1/ps. In addition, we present the most precise mean Bs lifetime taus, polarization amplitudes |A0|2, |A∥|2 and |A⊥|2, as well as strong phase deltaperp: taus = 458.6 +/- 7.6 (stat) +/- 3.6 (syst) microns |A0|2 = 0.524 +/- 0.013 (stat) +/- 0.015 (syst) |A∥|2 = 0.231 +/- 0.014 (stat) +/- 0.015 (syst) deltaperp = 2.95 +/- 0.64 (stat) +/- 0.07 (syst).