@article{636ad04517ff43599442aa56ee8788db,
title = "Search for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → bb¯ , in proton-proton collisions at √s = 13 TeV with the ATLAS detector",
abstract = "A search for flavour-changing neutral-current decays of a top quark into an up-type quark (either up or charm) and a light scalar particle X decaying into a bottom anti-bottom quark pair is presented. The search focuses on top-quark pair production where one top quark decays to qX, with X → bb¯ , and the other top quark decays according to the Standard Model, with the W boson decaying leptonically. The final state is thus characterised by an isolated electron or muon and at least four jets. Events are categorised according to the multiplicity of jets and jets tagged as originating from b-quarks, and a neural network is used to discriminate between signal and background processes. The data analysed correspond to 139 fb −1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, recorded with the ATLAS detector at the LHC. The 95% confidence-level upper limits between 0.019% and 0.062% are derived for the branching fraction B (t → uX) and between 0.018% and 0.078% for the branching fraction B (t → cX), for masses of the scalar particle X between 20 and 160 GeV. [Figure not available: see fulltext.]",
keywords = "Hadron-Hadron Scattering",
author = "{The ATLAS collaboration} and G. Aad and B. Abbott and Abbott, {D. C.} and K. Abeling and Abidi, {S. H.} and A. Aboulhorma and H. Abramowicz and H. Abreu and Y. Abulaiti and {Abusleme Hoffman}, {A. C.} and Acharya, {B. S.} and B. Achkar and {Adam Bourdarios}, C. and L. Adamczyk and L. Adamek and Addepalli, {S. V.} and J. Adelman and A. Adiguzel and S. Adorni and T. Adye and Affolder, {A. A.} and Y. Afik and Agaras, {M. N.} and J. Agarwala and A. Aggarwal and C. Agheorghiesei and Aguilar-Saavedra, {J. A.} and A. Ahmad and F. Ahmadov and Ahmed, {W. S.} and S. Ahuja and X. Ai and G. Aielli and I. Aizenberg and M. Akbiyik and {\AA}kesson, {T. P.A.} and Akimov, {A. V.} and {Al Khoury}, K. and Alberghi, {G. L.} and J. Albert and P. Albicocco and {Alconada Verzini}, {M. J.} and S. Alderweireldt and M. Aleksa and Aleksandrov, {I. N.} and C. Alexa and T. Alexopoulos and A. Alfonsi and L. Heinrich and E. Kourlitis",
note = "Publisher Copyright: {\textcopyright} 2023, The Author(s).",
year = "2023",
month = jul,
doi = "10.1007/JHEP07(2023)199",
language = "English",
volume = "2023",
journal = "Journal of High Energy Physics",
issn = "1126-6708",
publisher = "Springer Verlag",
number = "7",
}