Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in sqrt(s) = 7 TeV proton-proton collisions

TL;DR

This paper reports on searches for supersymmetric particles in proton-proton collisions at 7 TeV using the ATLAS detector, finding no deviations from the Standard Model and setting exclusion limits on certain supersymmetric models.

Contribution

First searches for supersymmetry with two leptons and missing transverse momentum at 7 TeV using ATLAS data, establishing new exclusion limits.

Findings

No excess events observed beyond Standard Model predictions.

Excluded supersymmetric production cross sections above 9.9 fb and 14.8 fb at 95% CL.

Excluded chargino masses up to 200 GeV in a simplified model.

Abstract

Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or mu. The analysis uses a data sample collected during the first half of 2011 that corresponds to a total integrated luminosity of 1 fb^-1 of sqrt{s} = 7 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Opposite-sign and same-sign dilepton events are separately studied, with no deviations from the Standard Model expectation observed. Additionally, in opposite- sign events, a search is made for an excess of same-flavour over different-flavour lepton pairs. Effective production cross sections in excess of 9.9 fb for opposite-sign events containing supersymmetric particles with missing transverse momentum greater than 250 GeV are excluded at 95% CL. For same-sign events containing supersymmetric particles with missing transverse momentum greater than 100 GeV, effective production cross sections in excess of 14.8 fb are excluded at 95% CL. The latter limit is interpreted in a simplified weak gaugino production model excluding chargino masses up to 200 GeV.