@misc{10481/85948,
year = {2023},
month = {8},
url = {https://hdl.handle.net/10481/85948},
abstract = {A search for flavor-changing neutral-current couplings between a top quark, an up or charm quark, and a Z boson is presented, using proton–proton collision data at √s=13  TeV collected by the ATLAS detector at the Large Hadron Collider. The analyzed data set corresponds to an integrated luminosity of 139  fb−1. The search targets both single-top-quark events produced as gq→tZ (with q=u, c) and top-quark-pair events, with one top quark decaying through the t→Zq channel. The analysis considers events with three leptons (electrons or muons), a b-tagged jet, possible additional jets, and missing transverse momentum. The data are found to be consistent with the background-only hypothesis and 95% confidence-level limits on the t→Zq branching ratios, assuming only tensor operators of the Standard Model effective field theory framework contribute to the tZq vertices. These are 6.2×10−5 (13×10−5) for t→Zu (t→Zc) for a left-handed tZq coupling, and 6.6×10−5 (12×10−5) in the case of a right-handed coupling. These results are interpreted as 95% CL upper limits on the strength of the corresponding couplings, yielding limits for |C(13)*uW| and |C(13)*uB| (|C(31)uW| and |C(31)uB|) of 0.15 (0.16), and limits for |C(23)*uW| and |C(23)*uB| (|C(32)uW| and |C(32)uB|) of 0.22 (0.21), assuming a new-physics energy scale ΛNP of 1 TeV.},
organization = {EU-ESF},
organization = {GenT Programmes Generalitat Valenciana, Spain},
organization = {La Caixa Banking Foundation},
organization = {PROMETEO},
organization = {H2020 Marie Skłodowska-Curie Actions
 		MSCA},
organization = {CERN},
organization = {European Research Council
 	ERC},
organization = {European Cooperation in Science and Technology
 		COST},
organization = {Generalitat de Catalunya},
organization = {Agencia Nacional de Promoción Científica y Tecnológica
 	ANPCyT},
organization = {Ministerio de Ciencia e Innovación
 	MICINN},
organization = {European Regional Development Fund
 	ERDF},
organization = {Agencia Nacional de Investigación y Desarrollo
 	ANID},
organization = {PIC (Spain)},
publisher = {American Physical Society},
title = {Search for flavor-changing neutral-current couplings between the top quark and the Z boson with proton-proton collisions at √s=13  TeV with the ATLAS detector},
doi = {10.1103/PhysRevD.108.032019},
author = {Aad, G. and Aguilar Saavedra, Juan Antonio and Rodríguez Chala, Mikael and Atlas Collaboration},
}