Lepton flavour violation in rare $\Lambda_b$ decays

TL;DR

This paper investigates lepton flavour violation in rare baryonic $ ext{Lambda}_b$ decays, providing model-independent bounds and exploring implications for new physics models, thus extending LFV studies beyond mesonic decays.

Contribution

It introduces a comprehensive analysis of LFV in $ ext{Lambda}_b$ baryonic decays using a full basis of New Physics operators, which is novel in this context.

Findings

Expected bounds on branching ratios in a model-independent framework

Analysis of LFV in specific new physics models

Discussion of the relationship between baryonic and mesonic LFV searches

Abstract

Lepton flavour violation (LFV) naturally occurs in many new physics models, specifically in those explaining the $B$ anomalies. While LFV has already been studied for mesonic decays, it is important to consider also baryonic decays mediated by the same quark transition. In this paper, we study LFV in the baryonic $\Lambda_b \to \Lambda \ell_1 \ell_2$ using for the first time a full basis of New Physics operators. We present expected bounds on the branching ratio in a model-independent framework and using two specific new physics models. Finally, we point out the interplay and orthogonality between the baryonic and mesonic LFV searches.