Measurement of the $B_{s}^{0} \rightarrow J/\psi \eta$ lifetime

TL;DR

This paper reports the first measurement of the effective lifetime of the $B_s^0$ meson in the $J/ ta$ decay mode using LHCb data, providing a key parameter for understanding $CP$ conservation and meson behavior.

Contribution

It presents the first measurement of the $B_s^0 ightarrow J/ ta$ effective lifetime, utilizing data from LHCb at 7 and 8 TeV.

Findings

Effective lifetime measured as 1.479 ± 0.034 (stat) ± 0.011 (syst) ps.

Assuming $CP$ conservation, this corresponds to the lifetime of the light $B_s^0$ eigenstate.

First such measurement in this decay mode.

Abstract

Using a data set corresponding to an integrated luminosity of $3 fb^{-1}$, collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV, the effective lifetime in the $B^0_s \rightarrow J/\psi \eta$ decay mode, $\tau_{\textrm{eff}}$, is measured to be $\tau_{\textrm{eff}} = 1.479 \pm 0.034~\textrm{(stat)} \pm 0.011 ~\textrm{(syst)}$ ps. Assuming $CP$ conservation, $\tau_{\textrm{eff}}$ corresponds to the lifetime of the light $B_s^0$ mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.