Search for lepton-flavor violation in different-flavor, high-mass final states in $pp$ collisions at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$ with the ATLAS detector

A search is performed for a heavy particle decaying into different-flavor, dilepton pairs ($e\mu $, $e\tau $ or $\mu \tau $), using $36.1\text{}\text{}{\mathrm{fb}}^{-1}$ of proton-proton collision data at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$ collected in 2015–2016 by the ATLAS detector at the Large Hadron Collider. No excesses over the Standard Model predictions are observed. Bayesian lower limits at the 95% credibility level are placed on the mass of a ${Z}^{\prime }$ boson, the mass of a supersymmetric $\tau $-sneutrino, and on the threshold mass for quantum black-hole production. For the ${Z}^{\prime }$ and sneutrino models, upper cross-section limits are converted to upper limits on couplings, which are compared with similar limits from low-energy experiments and which are more stringent for the $e\tau $ and $\mu \tau $ modes.