Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at √s=8  TeV using the ATLAS detector

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, et al. (2015) Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at √s=8  TeV using the ATLAS detector. Physical Review Letters, 114 (142001). ISSN 0031-9007

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Abstract

A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3  fb−1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in the azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38±0.04, in agreement with the standard model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95% confidence level.

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: 26 Apr 2017 09:31
Last Modified: 26 Apr 2017 10:02
URI: http://sro.sussex.ac.uk/id/eprint/67487

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Project NameSussex Project NumberFunderFunder Ref
ATLASG0275STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/I006048/1