Further search for supersymmetry at sqrt(s) = 7 TeV in final states with jets, missing transverse momentum and isolated leptons with the ATLAS detector

TL;DR

This paper reports a comprehensive search for supersymmetry at 7 TeV using ATLAS data, employing advanced analysis techniques to improve sensitivity and set new limits on SUSY models.

Contribution

It introduces a combined analysis of single- and multi-lepton channels with optimized signal regions, including a dedicated search for compressed SUSY scenarios.

Findings

No significant excess over Standard Model predictions was observed.

New limits were set on various SUSY models, extending previous constraints.

The analysis improved sensitivity through simultaneous fitting of event counts and distribution shapes.

Abstract

This work presents a new inclusive search for supersymmetry (SUSY) by the ATLAS experiment at the LHC in proton-proton collisions at a center-of-mass energy sqrt(s) = 7 TeV in final states with jets, missing transverse momentum and one or more isolated electrons and/or muons. The search is based on data from the full 2011 data-taking period, corresponding to an integrated luminosity of 4.7 inverse fb. Single- and multi-lepton channels are treated together in one analysis. An increase in sensitivity is obtained by simultaneously fitting the number of events in statistically independent signal regions, and the shapes of distributions within those regions. A dedicated signal region is introduced to be sensitive to decay cascades of SUSY particles with small mass differences ("compressed SUSY"). Background uncertainties are constrained by fitting to the jet multiplicity distribution in background control regions. Observations are consistent with Standard Model expectations, and limits are set or extended on a number of SUSY models.