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

The ATLAS collaboration

doi:10.1007/JHEP07(2023)199

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

The ATLAS collaboration

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

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.]

Original language	English
Article number	199
Journal	Journal of High Energy Physics
Volume	2023
Issue number	7
DOIs	https://doi.org/10.1007/JHEP07(2023)199
State	Published - Jul 2023
Externally published	Yes

Funding

We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; Minciencias, Colombia; MEYS CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MEiN, Poland; FCT, Portugal; MNE/IFA, Romania; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DSI/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TENMAK, Türkiye; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, CANARIE, Compute Canada and CRC, Canada; PRIMUS 21/SCI/017 and UNCE SCI/013, Czech Republic; COST, ERC, ERDF, Horizon 2020 and Marie Skłodowska-Curie Actions, European Union; Investissements d’Avenir Labex, Investissements d’Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and MINERVA, Israel; Norwegian Financial Mechanism 2014-2021, Norway; NCN and NAWA, Poland; La Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Göran Gustafssons Stiftelse, Sweden; The Royal Society and Leverhulme Trust, United Kingdom.

Keywords

Hadron-Hadron Scattering

Access to Document

10.1007/JHEP07(2023)199

Cite this

@article{d6ad6117e3cd48f99c53ced01296ecb2,

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 F. Alfonsi and Steinhebel, \{A. L.\}",

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",

number = "7",

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T1 - 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

AU - The ATLAS collaboration

AU - Aad, G.

AU - Abbott, B.

AU - Abbott, D. C.

AU - Abeling, K.

AU - Abidi, S. H.

AU - Aboulhorma, A.

AU - Abramowicz, H.

AU - Abreu, H.

AU - Abulaiti, Y.

AU - Abusleme Hoffman, A. C.

AU - Acharya, B. S.

AU - Achkar, B.

AU - Adam Bourdarios, C.

AU - Adamczyk, L.

AU - Adamek, L.

AU - Addepalli, S. V.

AU - Adelman, J.

AU - Adiguzel, A.

AU - Adorni, S.

AU - Adye, T.

AU - Affolder, A. A.

AU - Afik, Y.

AU - Agaras, M. N.

AU - Agarwala, J.

AU - Aggarwal, A.

AU - Agheorghiesei, C.

AU - Aguilar-Saavedra, J. A.

AU - Ahmad, A.

AU - Ahmadov, F.

AU - Ahmed, W. S.

AU - Ahuja, S.

AU - Ai, X.

AU - Aielli, G.

AU - Aizenberg, I.

AU - Akbiyik, M.

AU - Åkesson, T. P.A.

AU - Akimov, A. V.

AU - Al Khoury, K.

AU - Alberghi, G. L.

AU - Albert, J.

AU - Albicocco, P.

AU - Alconada Verzini, M. J.

AU - Alderweireldt, S.

AU - Aleksa, M.

AU - Aleksandrov, I. N.

AU - Alexa, C.

AU - Alexopoulos, T.

AU - Alfonsi, A.

AU - Alfonsi, F.

AU - Steinhebel, A. L.

PY - 2023/7

Y1 - 2023/7

N2 - 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.]

AB - 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.]

KW - Hadron-Hadron Scattering

UR - https://www.scopus.com/pages/publications/85174264679

U2 - 10.1007/JHEP07(2023)199

DO - 10.1007/JHEP07(2023)199

M3 - Article

AN - SCOPUS:85174264679

SN - 1126-6708

VL - 2023

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 7

M1 - 199

ER -

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

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Keywords

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