Search for supersymmetry at $\sqrt{s}=13$ TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector

TL;DR

This paper reports a search for supersymmetric particles using ATLAS detector data at 13 TeV, focusing on events with multiple jets and same-sign or multiple leptons, but finds no evidence of supersymmetry and sets new exclusion limits.

Contribution

First search at 13 TeV using these specific signatures, extending exclusion limits for gluino and squark masses in simplified supersymmetric models.

Findings

No significant excess over Standard Model expectations.

Excludes gluino masses up to 1.3 TeV for certain decay modes.

Excludes bottom squark masses up to 540 GeV.

Abstract

A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ($e$ or $\mu$) with the same electric charge or at least three isolated leptons. The search also utilises $b$-tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton-proton collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.2 fb$^{-1}$. No significant excess over the Standard Model expectation is observed. The results are interpreted in several simplified supersymmetric models and extend the exclusion limits from previous searches. In the context of exclusive production and simplified decay modes, gluino masses are excluded at 95% confidence level up to 1.1-1.3 TeV for light neutralinos (depending on the decay channel), and bottom squark masses are also excluded up to 540 GeV. In the former scenarios, neutralino masses are also excluded up to 550-850 GeV for gluino masses around 1 TeV.