Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in $\sqrt{s}$ = 13 TeV $pp$ collisions with the ATLAS detector

TL;DR

This paper reports a search for supersymmetric chargino-neutralino pairs decaying into three leptons at 13 TeV, using ATLAS data, finding no significant excess and setting mass exclusion limits up to 345 GeV.

Contribution

First search employing a recursive jigsaw reconstruction technique with laboratory-frame variables in three-lepton final states at the LHC.

Findings

No significant deviation from the Standard Model observed.

Exclusion limits set on chargino-neutralino masses up to 345 GeV.

Reproduction of previous excesses in low-mass three-lepton phase space.

Abstract

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell $W$ and $Z$ bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of $\sqrt{s}$ = 13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015-2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full dataset are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV.