Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

TL;DR

This paper measures the bottom-strange meson mixing phase _s using the full Fermilab Tevatron data set, providing results consistent with the standard model and improving precision on related parameters.

Contribution

It presents the first measurement of _s mixing phase _s using the complete Tevatron data set, enhancing the precision of _s related parameters.

Findings

Measured _s mixing phase _s consistent with standard model

Determined _s decay-width difference _s = 0.068 _s _s (stat) _s 0.009 (syst) ps

Estimated _s lifetime as 1.528 _s 0.019 (stat) _s 0.009 (syst) ps

Abstract

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> 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 sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.