# Searching new physics in rare $B$-meson decays into multiple muons

## TL;DR

This paper proposes new rare B-meson decay channels involving multiple muons as probes for new heavy vector bosons and light scalars predicted by beyond Standard Model theories, and assesses LHCb's sensitivity to these processes.

## Contribution

It identifies novel B-meson decay channels involving multiple muons as sensitive probes for new physics and evaluates the experimental reach of LHCb for detecting these rare decays.

## Key findings

- LHCb can test branching ratios as low as 9×10^{-12} for certain decay modes.
- New decay channels can probe interactions related to B anomalies and muon g-2.
- Potential to discover or constrain new heavy vector bosons and light scalars.

## Abstract

New heavy vector bosons and light scalars are predicted in a plethora of models of new physics. In particular, in new strongly interacting sectors they play the role of the $\rho$ and $\pi$ mesons in QCD. We show that some of their interactions, for example those required for the explanation of the $B$ anomalies and the $g-2$ of the muon, can be only probed in $B$ meson decays. We highlight new golden channels not yet studied experimentally, including $B^+ \rightarrow K^+(D^+)\mu^+\mu^-\mu^+\mu^-$ and $B^0\rightarrow K^{*0}\mu^+\mu^-\mu^+\mu^-$. Relying on generator level simulations for data taking with the LHCb detector, we determine the reach of this facility to the aforementioned processes. We show that branching ratios as small as $9\times 10^{-12}$ ($3.2\times 10^{-10}$) and $2.7\times 10^{-11}$ can be tested at the $95\, \%$ CL respectively.