Search for New Phenomena in t(t)overbar Events with Large Missing Transverse Momentum in Proton-Proton Collisions at root s=7 TeV with the ATLAS Detector


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

PHYSICAL REVIEW LETTERS, vol.108, no.4, 2012 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 108 Issue: 4
  • Publication Date: 2012
  • Doi Number: 10.1103/physrevlett.108.041805
  • Title of Journal : PHYSICAL REVIEW LETTERS

Abstract

A search for new phenomena in t (t) over bar events with large missing transverse momentum in proton-proton collisions at a center-of-mass energy of 7 TeV is presented. The measurement is based on 1: 04 fb(-1) of data collected with the ATLAS detector at the LHC. Contributions to this final state may arise from a number of standard model extensions. The results are interpreted in terms of a model where new top-quark partners are pair produced and each decay to an on-shell top (or antitop) quark and a long-lived undetected neutral particle. The data are found to be consistent with standard model expectations. A limit at 95% confidence level is set excluding a cross section times branching ratio of 1.1 pb for a top-partner mass of 420 GeVand a neutral particle mass less than 10 GeV. In a model of exotic fourth generation quarks, toppartner masses are excluded up to 420 GeV and neutral particle masses up to 140 GeV.