# $U(1)_{B_3-3L_\mu}$ gauge symmetry as a simple description of $b\to s$ anomalies

## TL;DR

This paper proposes a simple gauge extension of the Standard Model with a $U(1)_{B_3-3L_}$ symmetry to explain observed anomalies in B-meson decays, highlighting its minimal particle content and phenomenological implications.

## Contribution

It introduces a minimal $U(1)_{B_3-3L_}$ gauge symmetry model that accounts for $R(K)$ and $R(K^*)$ anomalies with specific fermion charge assignments.

## Key findings

- The model explains lepton non-universality in B decays.
- It predicts flavor-changing neutral currents involving second and third quark families.
- Constraints from current experiments are discussed.

## Abstract

We present a simple $U(1)_{B_3-3L_\mu}$ gauge Standard Model extension that can easily account for the anomalies in $R(K)$ and $R(K^*)$ reported by LHCb. The model is economical in its setup and particle content. Among the Standard Model fermions, only the third generation quark family and the second generation leptons transform non-trivially under the new $U(1)_{B_3-3L_\mu}$ symmetry. This leads to lepton non-universality and flavor changing neutral currents involving the second and third quark families. We discuss the relevant experimental constraints and some implications.