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

Journal Article (Journal Article)

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 s=13 TeV, corresponding to an integrated luminosity of 36.1 fb−1, 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 × 10−4 (2.4 × 10−4) on the t → uZ branching ratio and 2.4 × 10−4 (3.2 × 10−4) on the t → cZ branching ratio, constituting the most stringent limits to date.[Figure not available: see fulltext.].

Full Text

Duke Authors

Cited Authors

  • Aaboud, M; Aad, G; Abbott, B; Abdinov, O; Abeloos, B; Abidi, SH; AbouZeid, OS; Abraham, NL; Abramowicz, H; Abreu, H; Abulaiti, Y; Acharya, BS; Adachi, S; Adamczyk, L; Adelman, J; Adersberger, M; Adye, T; Affolder, AA; Afik, Y; Agheorghiesei, C; Aguilar-Saavedra, JA; Ahmadov, F; Aielli, G; Akatsuka, S; Akerstedt, H; Åkesson, TPA; Akilli, E; Akimov, AV; Alberghi, GL; Albert, J; Albicocco, P; Alconada Verzini, MJ; Alderweireldt, S; Aleksa, M; Aleksandrov, IN; Alexa, C; Alexander, G; Alexopoulos, T; Alhroob, M; Ali, B; Aliev, M; Alimonti, G; Alison, J; Alkire, SP; Allaire, C; Allbrooke, BMM; Allen, BW; Allport, PP; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Alshehri, AA; Alstaty, MI; Alvarez Gonzalez, B; Álvarez Piqueras, D; Alviggi, MG; Amadio, BT; Amaral Coutinho, Y; Amelung, C; Amidei, D; Amor Dos Santos, SP; Amoroso, S; Anastopoulos, C; Ancu, LS; Andari, N; Andeen, T; Anders, CF; Anders, JK; Anderson, KJ; Andreazza, A; Andrei, V; Angelidakis, S; Angelozzi, I; Angerami, A; Anisenkov, AV; Annovi, A; Antel, C; Antonelli, M; Antonov, A; Antrim, DJA; Anulli, F; Aoki, M; Aperio Bella, L; Arabidze, G; Arai, Y; Araque, JP; Araujo Ferraz, V; Arce, ATH; Ardell, RE; Arduh, FA; Arguin, JF; Argyropoulos, S; Arik, M; Armbruster, AJ; Armitage, LJ; Arnaez, O; Arnold, H; Arratia, M; Arslan, O

Published Date

  • July 1, 2018

Published In

Volume / Issue

  • 2018 / 7

Electronic International Standard Serial Number (EISSN)

  • 1029-8479

International Standard Serial Number (ISSN)

  • 1126-6708

Digital Object Identifier (DOI)

  • 10.1007/JHEP07(2018)176

Citation Source

  • Scopus