Lifetime Difference and CP Asymmetry in the Bs -> J/psi phi decay

TL;DR

This paper measures the lifetime difference and CP violating phase in Bs -> J/psi phi decays, providing results consistent with the Standard Model and finding no evidence of CP violation.

Contribution

It presents the first measurement of the lifetime difference and CP phase in Bs decays using 1.7 fb^-1 of data from the Tevatron, with results aligning with Standard Model predictions.

Findings

Measured lifetime difference DeltaGamma = 0.076 +0.059-0.063 ps^-1

Measured Bs lifetime ctau_s = 456 +-13 (stat.) +- 7 (syst.) m^-6

No evidence for CP violation found

Abstract

The Bs meson is an interesting particle to study because a sizable mixing induced CP violation in the Bs-Bsbar system would be an indication for physics beyond the Standard Model. In this paper we present a measurement of the lifetime difference DeltaGamma between the Bs mass eigenstates and the CP violating phase in the decay Bs -> J/psi phi. In 1.7 fb^-1 of data collected with the CDF II detector at the Tevatron ppbar collider we measure DeltaGamma = 0.076 +0.059-0.063 (stat.) +- 0.006 (syst.) ps^-1, well consistent with the Standard Model prediction, and a mean Bs lifetime of ctau_s = 456 +-13 (stat.) +- 7 (syst.) m^-6. We find no evidence for CP violation.