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Title: Evidence for single top-quark production in the s-channel in proton–proton collisions at √s = 8TeV with the ATLAS detector using the Matrix Element Method

This Letter presents evidence for single top-quark production in the s-channel using proton–proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the CERN Large Hadron Collider. The analysis is performed on events containing one isolated electron or muon, large missing transverse momentum and exactly two b-tagged jets in the final state. The analysed data set corresponds to an integrated luminosity of 20.3 fb-1. The signal is extracted using a maximum-likelihood fit of a discriminant which is based on the matrix element method and optimized in order to separate single-top-quark s-channel events from the main background contributions, which are top-quark pair production and W boson production in association with heavy-flavour jets. The measurement leads to an observed signal significance of 3.2 standard deviations and a measured cross-section of σs = 4.8 ± 0.8(stat.)-1.3+1.6(syst.) pb, which is consistent with the Standard Model expectation. As a result, the expected significance for the analysis is 3.9 standard deviations.
Authors:
 [1]
  1. Aix-Marseille Univ. and CNRS/IN2P3, Marseille (France). et al.
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 756; Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Contributing Orgs:
ATLAS Collaboration
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
OSTI Identifier:
1241427
Alternate Identifier(s):
OSTI ID: 1242386