Measurement of the bottom-strange meson mixing phase in the full CDF data set

Abstract

We report a measurement of the bottom-strange meson mixing phase βs using the time evolution of Bs0→J/ ψ(→μ+μ-)(→K+K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at √s=1.96TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6fb -1 of integrated luminosity. We report confidence regions in the two-dimensional space of βs and the Bs0 decay-width difference ΔΓs and measure βs [-π/2,-1.51] [-0.06,0.30] [1.26,π/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of βs, we also determine ΔΓs=0.068±0. 026(stat)±0.009(syst)ps-1 and the mean Bs0 lifetime τs=1.528±0.019(stat)±0.009(syst)ps, which are consistent and competitive with determinations by other experiments. © 2012 American Physical Society.