Searches for lepton-flavour-violating decays of the Higgs boson in s=13 TeV pp collisions with the ATLAS detector

Abstract

This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H→eτand H→μτ, performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton–proton collisions at a centre-of-mass energy √s=13TeV, corresponding to an integrated luminosity of 36.1fb−1. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the lepton-flavour-violating branching ratios are 0.47%(0.34+0.13−0.10%) and 0.28%(0.37+0.14−0.10%) for H→eτand H→μτ, respectively.