A search for $B-L$ $R$-parity-violating top squarks in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS experiment

TL;DR

This paper reports a search for supersymmetric top squarks decaying via R-parity violation in proton-proton collisions at 13 TeV, setting mass exclusion limits between 600 GeV and 1.5 TeV.

Contribution

First search for R-parity-violating top squarks decaying to leptons and jets at 13 TeV with ATLAS, establishing new mass exclusion limits.

Findings

No significant excess over Standard Model background.

Excluded stop masses between 600 GeV and 1.5 TeV for certain decay branching ratios.

Set 95% confidence level exclusion limits.

Abstract

A search is presented for the direct pair production of the stop, the supersymmetric partner of the top quark, that decays through an $R$-parity-violating coupling to a final state with two leptons and two jets, at least one of which is identified as a $b$-jet. The dataset corresponds to an integrated luminosity of 36.1 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of $\sqrt{s} = 13$ TeV, collected in 2015 and 2016 by the ATLAS detector at the LHC. No significant excess is observed over the Standard Model background, and exclusion limits are set on stop pair production at a 95% confidence level. Lower limits on the stop mass are set between 600 GeV and 1.5 TeV for branching ratios above 10% for decays to an electron or muon and a $b$-quark.