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Search for flavour-changing neutral current top-quark decays t > qZ in proton-proton collisions at sqrt (s) = 13 TeV with the ATLAS detector

journal contribution
posted on 2023-06-09, 15:47 authored by N L Abraham, Benedict AllbrookeBenedict Allbrooke, Lily AsquithLily Asquith, Alessandro CerriAlessandro Cerri, C A Chavez Barajas, Antonella De SantoAntonella De Santo, Samuel Jones, G Lerner, F Miano, Fabrizio SalvatoreFabrizio Salvatore, I Santoyo Castillo, C Y Shehu, Kate ShawKate Shaw, Thomas StevensonThomas Stevenson, K Suruliz, Mark SuttonMark Sutton, Fabio Tresoldi, Iacopo Vivarelli, E Winkels, O J Winston, The ATLAS Collaboration, others
A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of p s = 13TeV, corresponding to an integrated luminosity of 36.1 fb1, are analysed. The search is performed using top quark pair events, with one top quark decaying through the t > qZ (q = u; c) flavour changing neutral-current channel, and the other through the dominant Standard Model mode t > bW. Only Z boson decays into charged leptons and leptonic W boson decays are considered as signal. Consequently, the final-state topology is characterized by the presence of three isolated charged leptons (electrons or muons), at least two jets, one of the jets originating from a b-quark, and missing transverse momentum from the undetected neutrino. The data are consistent with Standard Model background contributions, and at 95% confidence level the search sets observed (expected) upper limits of 1:7 x 10-4 (2:4 x 10-4) on the t > uZ branching ratio and 2:4 _ 104 (3:2 _ 104) on the t > cZ branching ratio, constituting the most stringent limits to date.

History

Publication status

  • Published

File Version

  • Published version

Journal

Journal of High Energy Physics

ISSN

1126-6708

Publisher

Institute of Physics

Volume

7

Page range

176

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Experimental Particle Physics Research Group Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2018-11-08

First Compliant Deposit (FCD) Date

2018-11-07

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