Search for new phenomena in different-flavour high-mass dilepton final states in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

TL;DR

This paper reports a search for heavy particles decaying into different-flavour dilepton pairs in proton-proton collisions at 13 TeV, setting new limits on various beyond-Standard-Model particles with no observed excess.

Contribution

It provides the first limits on lepton-flavour-violating $Z'$ bosons, supersymmetric $ au$ sneutrinos, and quantum black holes using ATLAS data at 13 TeV.

Findings

No excess observed over Standard Model predictions.

Limits set on $Z'$ boson masses up to 3.0 TeV.

Limits set on $ au$ sneutrino masses up to 2.3 TeV.

Abstract

A search is performed for a heavy particle decaying into different flavour dilepton pairs ($e\mu$, $e\tau$ or $\mu\tau$), using 3.2 $fb^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ TeV collected in 2015 by the ATLAS detector at the Large Hadron Collider. No excess over the Standard Model prediction is observed. Limits at the 95% credibility level are set on the mass of a $Z^{\prime}$ boson with lepton-flavour-violating couplings at 3.0, 2.7 and 2.6 TeV, and on the mass of a supersymmetric $\tau$ sneutrino with $R$-parity-violating couplings at 2.3, 2.2 and 1.9 TeV, for $e\mu$, $e\tau$ and $\mu\tau$ final states, respectively. The results are also interpreted as limits on the threshold mass for quantum black hole production.