Search for scalar top quark pair production in natural gauge mediated supersymmetry models with the ATLAS detector in pp collisions at root s=7 TeV


Aad G., Abbott B., Abdallah J., Khalek S. A. , Abdelalim A. A. , Abdinov O., ...More

PHYSICS LETTERS B, vol.715, pp.44-60, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 715
  • Publication Date: 2012
  • Doi Number: 10.1016/j.physletb.2012.07.010
  • Journal Name: PHYSICS LETTERS B
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.44-60
  • Middle East Technical University Affiliated: Yes

Abstract

The results of a search for pair production of the lighter scalar partners of top quarks ((t) over bar (1)) in 2.05 fb(-1) of pp collisions at root s = 7 TeV using the ATLAS experiment at the LHC are reported. Scalar top quarks are searched for in events with two same flavour opposite-sign leptons (e, mu) with invariant mass consistent with the Z boson mass, large missing transverse momentum and jets in the final state. At least one of the jets is identified as originating from a b-quark. No excess over Standard Model expectations is found. The results are interpreted in the framework of R-parity conserving, gauge mediated Supersymmetry breaking 'natural' scenarios, where the neutralino ((chi) over bar (0)(1)) is the next-to-lightest supersymmetric particle. Scalar top quark masses up to 310 GeV are excluded for 115 GeV m(<(chi) over bar1)(0) 230 GeV at 95% confidence level, reaching an exclusion of m(<(t) over bar1) 330 GeV for m(<(chi) over bar1)(0) = 190 GeV. Scalar top quark masses below 240 GeV are excluded for all values of m((chi) over bar1)(0) > m(z). (c) 2012 CERN. Published by Elsevier B.V. All rights reserved.