Measurement of $\tau_{L}$ using the $B_{s}^{0} \to J/\psi \eta$ decay mode

TL;DR

This paper reports a precise measurement of the $B_{s}^{0}$ meson lifetime $ au_{L}$ using the $B_{s}^{0} o J/ar{ u} ext{eta}$ decay mode with data from the LHCb detector, combining new and previous results for improved accuracy.

Contribution

The paper presents the first measurement of $ au_{L}$ using the $B_{s}^{0} o J/ar{ u} ext{eta}$ decay mode and combines it with previous data for a more precise estimate.

Findings

Measured $ au_{L}$ as 1.445 ± 0.016 (stat) ± 0.008 (syst) ps.

Combined $ au_{L}$ value is 1.452 ± 0.014 (stat) ± 0.007 (uncorrelated syst) ± 0.002 (correlated syst) ps.

Improves the precision of $B_{s}^{0}$ lifetime measurements.

Abstract

Using a proton-proton collision data sample collected by the LHCb detector and corresponding to an integrated luminosity of 5.7 $\text{fb}^{-1}$, the lifetime of the $B_{s}^{0}$ mass eigenstate, $\tau_{L}$, is measured using $B_{s}^{0} \to J/\psi \eta$ decay mode to be $\tau_{L}$ = 1.445 $\pm$ 0.016(stat) $\pm$ 0.008(syst) ps. A combination of this result with a previous LHCb analysis using an independent dataset corresponding to 3 $\text{fb}^{-1}$ of integrated luminosity gives $\tau_{L}$ = 1.452 $\pm$ 0.014 $\pm$ 0.007 $\pm$ 0.002 ps, where the first uncertainty is statistical, the second due to the uncorrelated part of the systematic uncertainty and the third due to the correlated part of the systematic uncertainty.