Probes of flavour symmetry and violation with top quarks in ATLAS and CMS

TL;DR

This paper reports on searches and measurements related to flavour symmetry and violation in top quark interactions using extensive data from the ATLAS and CMS experiments at the LHC, focusing on rare processes and universality tests.

Contribution

It provides new experimental results on charged lepton flavour violation, baryon number violation, neutral heavy leptons, and tests of lepton flavour universality in top quark events.

Findings

No evidence of charged lepton flavour violation found.

Constraints set on neutral heavy lepton parameters.

Precise measurement of lepton flavour universality consistent with the Standard Model.

Abstract

Results are presented of searches and measurements in the top quark sector by the ATLAS and CMS experiments. These analyses use data from proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded during Run 2 at the Large Hadron Collider and corresponding to integrated luminosities of 138-140 fb$^{-1}$. Searches are carried out for charged lepton flavour violation, baryon number violation and the presence of neutral heavy leptons. A precise measurement of lepton flavour universality between electrons and muons originating from top quark-antiquark events is also presented.