Ústav technické a experimentální fyziky Institute of Experimental and Applied Physics

Search for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → b(b)over-bar, in proton-proton collisions at √s=13 TeV with the ATLAS detector

NázevTitle
Search for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → b(b)over-bar, in proton-proton collisions at √s=13 TeV with the ATLAS detectorSearch for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → b(b)over-bar, in proton-proton collisions at √s=13 TeV with the ATLAS detector
Druh výsledkuResult type
Článek v časopiseJournal article
AutořiAuthors
G. Aad, B. Abbott, D. C. Abbott, K. Abeling, B. Ali, K. Augsten, B. Bergmann, T. Billoud, M. Havránek, Z. Hubáček, P. Jačka, S. Mondal, M. Myška, L. Novotný, V. Petousis, R. Polifka, S. Pospíšil, K. Smolek, A. Sopczak, V. Vacek, P. Vokáč, O. Zaplatílek
DOIDOI
10.1007/JHEP07(2023)199
Časopis / citaceJournal / citation
Journal of High Energy Physics. 2023, 2023(7), ISSN 1029-8479.
RokYear
2023
JazykLanguage
eng
WoSWoS
001061847500001
ScopusScopus
2-s2.0-85174264679
RIVRIV
RIV/68407700:21220/23:00372895!RIV24-MSM-21220___
ProjektProject
Centrum pokročilých aplikovaných přírodních vědCenter for advanced applied sciences; CERN-CZ III - Výzkumná infrastruktura pro experimenty v CERN - LM2023040 (2023–2026)CERN-CZ III - Výzkumná infrastruktura pro experimenty v CERN - LM2023040 (2023–2026)

AbstraktAbstract

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 -> b (b) over bar, 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 13TeV, 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.

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 -> b (b) over bar, 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 13TeV, 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.