Searches for Lepton Flavour Violation and Lepton Number Violation in Hadron Decays

TL;DR

This paper reviews recent experimental searches for lepton flavour and lepton number violation in hadron decays, highlighting the first such search for au decay at a hadron collider and presenting new upper limits.

Contribution

It reports the first search for lepton flavour violating au decay at a hadron collider and provides new upper exclusion limits comparable to previous B factory results.

Findings

First search for au o \mu ext{ extminus} ext{ extminus} ext{ extminus} ext{ extgreater} at a hadron collider

New upper limits on lepton flavour violating decays

Comparable sensitivity to B factory experiments

Abstract

In the Standard Model of particle physics, lepton flavour and lepton number are conserved quantities although no fundamental symmetry demands their conservation. I present recent results of searches for lepton flavour and lepton number violating hadron decays measured at the B factories and LHCb. In addition, the LHCb collaboration has recently performed a search for the lepton flavour violating decay \tau^- \to \mu^-\mu^-\mu^+. The obtained upper exclusion limit, that has been presented in this talk for the first time, is of the same order of magnitude as those observed at the B factories. This is the first search for a lepton flavour violating \tau decay at a hadron collider.