Allbrooke, B M M, Asquith, L, Cerri, A, Chavez Barajas, C A, De Santo, A, Salvatore, F, Santoyo Castillo, I, Suruliz, K, Sutton, M R, Vivarelli, I and The ATLAS Collaboration, (2016) Evidence for single top-quark production in the s-channel in proton–proton collisions at √s = 8 TeV with the ATLAS detector using the Matrix Element Method. Physics Letters B, 756. pp. 228-246. ISSN 0370-2693

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Abstract

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. The expected significance for the analysis is 3.9 standard deviations.

Item Type:	Article
Schools and Departments:	School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups:	Experimental Particle Physics Research Group
Subjects:	Q Science > QC Physics
Depositing User:	Billy Wichaidit
Date Deposited:	10 Apr 2017 12:53
Last Modified:	10 Apr 2017 12:56
URI:	http://sro.sussex.ac.uk/id/eprint/67324

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