Search for the lepton-flavor violating decay $B^0_s\to\phi\mu^\pm\tau^\mp$

TL;DR

This study searches for rare lepton-flavor violating decays of the $B^0_s$ meson into a $ au$ and a $ ext{phi}$ meson, using LHCb data, and sets an upper limit on the decay's branching fraction.

Contribution

First search for the lepton-flavor violating decay $B^0_s o ext{phi} au ext{mu}$ using LHCb data, establishing an upper limit on its branching fraction.

Findings

No significant signal observed.

Upper limit on branching fraction set at $1.0\times 10^{-5}$.

Analysis used 9 fb$^{-1}$ of data from 7, 8, and 13 TeV collisions.

Abstract

A search for the lepton-flavor violating decays $B^0_s\to\phi\mu^\pm\tau^\mp$ is presented, using a sample of proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of $9\,\text{fb}^{-1}$. The $\tau$ leptons are selected using decays with three charged pions. No significant excess is observed, and an upper limit on the branching fraction is determined to be ${\cal B}( B^0_s\to\phi\mu^\pm\tau^\mp) < 1.0\times 10^{-5}$ at 90% confidence level.