Search for decays of neutral beauty mesons into four muons

TL;DR

This paper reports a search for rare four-muon decays of neutral beauty mesons using LHCb data, setting upper limits on their branching fractions due to no observed signal.

Contribution

First search for non-resonant four-muon decays of B mesons using full Run 1 LHCb data, establishing new upper limits on their branching fractions.

Findings

No signal observed for the decays.

Upper limits on branching fractions set at 95% confidence level.

Results constrain new physics models predicting these decays.

Abstract

A search for the non-resonant decays $B^0_s \rightarrow \mu^{+}\mu^{-}\mu^{+}\mu^{-}$ and $B^0 \rightarrow \mu^{+}\mu^{-}\mu^{+}\mu^{-}$ is presented. The measurement is performed using the full Run 1 data set collected in proton-proton collisions by the LHCb experiment at the LHC. The data correspond to integrated luminosities of $1$ and $2~\mathrm{fb}^{-1}$ collected at centre-of-mass energies of $7$ and $8~\mathrm{TeV}$, respectively. No signal is observed and upper limits on the branching fractions of the non-resonant decays at $95\%$ confidence level are determined to be \mathcal{B}(B^0_s \rightarrow \mu^{+}\mu^{-}\mu^{+}\mu^{-}) & < 2.5 \times 10^{-9} \mathcal{B}(B^0 \rightarrow \mu^{+}\mu^{-}\mu^{+}\mu^{-}) & < 6.9 \times 10^{-10}.