TY - JOUR
T1 - Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb−1 of pp collisions at s=13TeV with the ATLAS experiment
AU - The ATLAS Collaboration
AU - Aad, G.
AU - Abbott, B.
AU - Abbott, D. C.
AU - Abed Abud, A.
AU - Abeling, K.
AU - Abhayasinghe, D. K.
AU - Abidi, S. H.
AU - Abouzeid, O. S.
AU - Abraham, N. L.
AU - Abramowicz, H.
AU - Abreu, H.
AU - Abulaiti, Y.
AU - Acharya, B. S.
AU - Achkar, B.
AU - Adachi, S.
AU - Adam, L.
AU - Adam Bourdarios, C.
AU - Adamczyk, L.
AU - Adamek, L.
AU - Adelman, J.
AU - Adersberger, M.
AU - Adiguzel, A.
AU - Adorni, S.
AU - Adye, T.
AU - Affolder, A. A.
AU - Afik, Y.
AU - Agapopoulou, C.
AU - Agaras, M. N.
AU - Aggarwal, A.
AU - Agheorghiesei, C.
AU - Aguilar-Saavedra, J. A.
AU - Ahmadov, F.
AU - Ahmed, W. S.
AU - Ai, X.
AU - Aielli, G.
AU - Akatsuka, S.
AU - Åkesson, T. P.A.
AU - Akilli, E.
AU - Akimov, A. V.
AU - Al Khoury, K.
AU - Alberghi, G. L.
AU - Albert, J.
AU - Alconada Verzini, M. J.
AU - Alderweireldt, S.
AU - Aleksa, M.
AU - Aleksandrov, I. N.
AU - Iizawa, T.
AU - Mitani, T.
AU - Morinaga, M.
AU - Yorita, K.
N1 - Funding Information:
We acknowledge the support of ANPCyT , Argentina; YerPhI , Armenia; ARC , Australia; BMWFW and FWF , Austria; ANAS , Azerbaijan; SSTC , Belarus; CNPq and FAPESP , Brazil; NSERC , NRC and CFI , Canada; CERN ; CONICYT , Chile; CAS , MOST and NSFC , China; COLCIENCIAS , Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC , Denmark; IN2P3-CNRS , CEA-DRF/IRFU , France; SRNSFG , Georgia; BMBF , HGF , and MPG , Germany; GSRT , Greece; RGC , Hong Kong SAR , China; ISF and Benoziyo Center , Israel; INFN , Italy; MEXT and JSPS , Japan; CNRST , Morocco; NWO , Netherlands; RCN , Norway; MNiSW and NCN , Poland; FCT , Portugal; MNE/IFA , Romania; MES of Russia and NRC KI , Russian Federation; JINR ; MESTD , Serbia; MSSR , Slovakia; ARRS and MIZŠ , Slovenia; DST/NRF , South Africa; MINECO , Spain; SRC and Wallenberg Foundation , Sweden; SERI , SNSF and Cantons of Bern and Geneva , Switzerland; MOST , Taiwan; TAEK , Turkey; STFC , United Kingdom; DOE and NSF , United States of America. In addition, individual groups and members have received support from BCKDF , Canarie , CRC and Compute Canada , Canada; COST , ERC , ERDF , Horizon 2020 , and Marie Skłodowska-Curie Actions , European Union; Investissements d' Avenir Labex and Idex , 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 GIF , Israel; CERCA Programme Generalitat de Catalunya , Spain; The Royal Society and Leverhulme Trust , United Kingdom.
PY - 2020/1/10
Y1 - 2020/1/10
N2 - A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5).
AB - A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5).
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UR - http://www.scopus.com/inward/citedby.url?scp=85075235650&partnerID=8YFLogxK
U2 - 10.1016/j.physletb.2019.135082
DO - 10.1016/j.physletb.2019.135082
M3 - Article
AN - SCOPUS:85075235650
VL - 800
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
M1 - 135082
ER -