Search for lepton-flavour-violating $H\toμτ$ decays of the Higgs boson with the ATLAS detector

Abstract

A direct search for lepton-flavour-violating (LFV) $H\toμτ$ decays of the recently discovered Higgs boson with the ATLAS detector at the LHC is presented. The analysis is performed in the $H\toμτ_{\mathrm{had}}$ channel, where $τ_{\mathrm{had}}$ is a hadronically decaying $τ$-lepton. The search is based on the data sample of proton--proton collisions collected by the ATLAS experiment corresponding to an integrated luminosity of 20.3 fb$^{-1}$ at a centre-of-mass energy of $\sqrt{s}=8$ TeV. No statistically significant excess of data over the predicted background is observed. The observed (expected) 95% confidence-level upper limit on the branching fraction, Br($H\toμτ$), is 1.85% (1.24%).

Comments: 15 pages plus author list + cover pages (31 pages total), 3 figures, 3 tables, submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2014-08/