Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at SQUARE ROOTs=13 TeV

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F23%3A10476598" target="_blank" >RIV/00216208:11320/23:10476598 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=j5lU.llYnl" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=j5lU.llYnl</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2022.137379" target="_blank" >10.1016/j.physletb.2022.137379</a>

Result language

angličtina

Original language name

Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at SQUARE ROOTs=13 TeV

Original language description

This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly sup-pressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in pp collisions at &amp; RADIC;s =13 TeV during Run 2 of the LHC, corresponding to an integrated luminosity of 139 fb-1. Both FCNC top-quark production and decay are considered. The final state consists of a charged lepton, missing transverse momentum, a b-tagged jet, one high-momentum photon and possibly additional jets. A multiclass deep neural network is used to classify events either as signal in one of the two categories, FCNC production or decay, or as background. No significant ex-cess of events over the background prediction is observed and 95% CL upper limits are placed on the strength of left-and right-handed FCNC interactions. The 95% CL bounds on the branching fractions for the FCNC top-quark decays, estimated (expected) from both top-quark production and decay, are B(t &amp; RARR; u &amp; gamma; ) &lt; 0.85 (0.88+0.37 -0.25) x 10-5 and B(t &amp; RARR; c &amp; gamma; ) &lt; 4.2 (3.40+1.35-0.95) x 10-5 for a left-handed tq &amp; gamma; cou-pling, and B(t &amp; RARR; u &amp; gamma; ) &lt; 1.2 (1.20+0.50 -0.33) x10-5 and B(t &amp; RARR; c &amp; gamma; ) &lt; 4.5 (3.70+1.47 -1.03) x10-5 for a right-handed coupling

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10300 - Physical sciences

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

ISSN

0370-2693

e-ISSN

1873-2445

Volume of the periodical

842

Issue of the periodical within the volume

Jul

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

22

Pages from-to

137379

UT code for WoS article

001023760300001

EID of the result in the Scopus database

2-s2.0-85146929561