Measurement of Lifetime and Decay-Width Difference in B0s -> J/psi phi Decays

TL;DR

This paper reports precise measurements of the B0s meson lifetime and decay-width difference using data from the Fermilab Tevatron, providing important tests of the Standard Model and CP conservation.

Contribution

The study presents the most precise measurements to date of B0s lifetime and width difference, assuming CP conservation, using 1.7 fb^-1 of data from the CDF II detector.

Findings

Measured DeltaGamma = 0.076^+0.059_-0.063 ps^-1

Measured tau = 1.52 +- 0.04 (stat.) +- 0.02 (syst.) ps

Results are consistent with CP conservation

Abstract

We measure the mean lifetime, tau=2/(Gamma_L+Gamma_H), and the width difference, DeltaGamma=Gamma_L-Gamma_H, of the light and heavy mass eigenstates of the B0s meson, B0sL and B0sH, in B0s -> J/psi phi decays using 1.7 fb^-1 of data collected with the CDF II detector at the Fermilab Tevatron ppbar collider. Assuming CP conservation, a good approximation for the B0s system in the Standard Model, we obtain DeltaGamma = 0.076^+0.059_-0.063 (stat.) +- 0.006 (syst.) ps^-1 and tau = 1.52 +- 0.04 (stat.) +- 0.02 (syst.) ps, the most precise measurements to date. Our constraints on the weak phase and DeltaGamma are consistent with CP conservation. Dedicated to the memory of our dear friend and colleague, Michael P. Schmidt