Measurement of the effective B_s^0 -> J/{\psi} K_S^0 lifetime

TL;DR

This paper presents the first measurement of the effective B_s^0 -> J/ψ K_S^0 lifetime and an updated branching fraction using 1.0 fb^{-1} of LHCb data at 7 TeV, providing key insights into B_s^0 decay properties.

Contribution

It provides the first measurement of the B_s^0 -> J/ψ K_S^0 effective lifetime and an updated branching fraction with improved precision.

Findings

Effective B_s^0 -> J/ψ K_S^0 lifetime measured as 1.75 +/- 0.12 (stat) +/- 0.07 (syst) ps.

Branching fraction BR(B_s^0 -> J/ψ K_S^0) measured as (1.97 +/- 0.23) x 10^{-5}.

Results improve understanding of B_s^0 decay dynamics.

Abstract

This paper reports the first measurement of the effective B_s^0 -> J/{\psi} K_S^0 lifetime and an updated measurement of its time-integrated branching fraction. Both measurements are performed with a data sample, corresponding to an integrated luminosity of 1.0 fb^{-1} of pp collisions, recorded by the LHCb experiment in 2011 at a centre-of-mass energy of 7 TeV. The results are: tau_J/{\psi}K_S^0 = 1.75 +/- 0.12 (stat) +/- 0.07 (syst) and BR(B_s^0 -> J/{\psi} K_S^0) = (1.97 +/- 0.23) X 10^{-5}. For the latter measurement, the uncertainty includes both statistical and systematic sources.