Measurement of the ttZ and ttW cross sections in proton-proton collisions at s = 13 TeV with the ATLAS detector

Abraham, N L, Allbrooke, B M M, Asquith, L, Cerri, A, Chavez Barajas, C A, DeSanto, A, Jones, S D, Lerner, G, Miano, F, Salvatore, F, Santoyo Castillo, I, Shaw, K, Stevenson, T J, Suruliz, K, Sutton, M R, Tresoldi, F, Trovato, F, Vivarelli, I, Winkels, E, Winston, O J and The ATLAS Collaboration, (2019) Measurement of the ttZ and ttW cross sections in proton-proton collisions at s = 13 TeV with the ATLAS detector. Physical Review D (PRD), 99 (072009). ISSN 2470-0010

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Abstract

A measurement of the associated production of a top-quark pair (t ̄t) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1 fb−1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The t ̄tZ and t ̄tW production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are σt ̄tZ 1⁄4 0.95 � 0.08stat � 0.10syst pb and σt ̄tW 1⁄4 0.87 � 0.13stat � 0.14syst pb in agreement with the Standard Model predictions. The measurement of the t ̄tZ cross section is used to set constraints on effective field theory operators which modify the t ̄tZ vertex.

Item Type: Article
Keywords: ATLAS, particle physics, top quark
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics > QC0770 Nuclear and particle physics. Atomic energy. Radioactivity > QC0793 Elementary particle physics
Depositing User: Iacopo Vivarelli
Date Deposited: 29 Oct 2019 11:02
Last Modified: 29 Oct 2019 16:00
URI: http://sro.sussex.ac.uk/id/eprint/87619

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