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

Understand

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.