TY - JOUR

T1 - Search for flavor-changing neutral currents in top quark decays t→Hc and t→Hu in multilepton final states in proton-proton collisions at √s=13 TeV with the ATLAS detector

AU - Barton, Adam Edward

AU - Beattie, Michael

AU - Bertram, Iain Alexander

AU - Borissov, Guennadi

AU - Bouhova-Thacker, Evelina Vassileva

AU - Fox, Harald

AU - Henderson, Robert Charles William

AU - Jones, Roger William Lewis

AU - Kartvelishvili, Vakhtang

AU - Long, Robin Eamonn

AU - Love, Peter Allan

AU - Muenstermann, Daniel Matthias Alfred

AU - Parker, Adam Jackson

AU - Skinner, Malcolm

AU - Smizanska, Maria

AU - Tee, Amy

AU - Walder, James William

AU - Wharton, Andrew Mark

AU - Whitmore, Ben

AU - The ATLAS collaboration

PY - 2018/8/6

Y1 - 2018/8/6

N2 - Flavor-changing neutral currents are not present in the Standard Model at tree level and are suppressed in loop processes by the unitarity of the Cabibbo-Kobayashi-Maskawa matrix; the corresponding rates for top quark decay processes are experimentally unobservable. Extensions of the Standard Model can generate new flavor-changing neutral current processes, leading to signals which, if observed, would be unambiguous evidence of new interactions. A data set corresponding to an integrated luminosity of 36.1 fb − 1 of p p collisions at a center-of-mass energy of √s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider is used to search for top quarks decaying to up or charm quarks with the emission of a Higgs boson, with subsequent Higgs boson decay to final states with at least one electron or muon. No signal is observed and limits on the branching fractions B ( t → H c ) < 0.16 % and B ( t → H u ) < 0.19 % at 95% confidence level are obtained (with expected limits of 0.15% in both cases).

AB - Flavor-changing neutral currents are not present in the Standard Model at tree level and are suppressed in loop processes by the unitarity of the Cabibbo-Kobayashi-Maskawa matrix; the corresponding rates for top quark decay processes are experimentally unobservable. Extensions of the Standard Model can generate new flavor-changing neutral current processes, leading to signals which, if observed, would be unambiguous evidence of new interactions. A data set corresponding to an integrated luminosity of 36.1 fb − 1 of p p collisions at a center-of-mass energy of √s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider is used to search for top quarks decaying to up or charm quarks with the emission of a Higgs boson, with subsequent Higgs boson decay to final states with at least one electron or muon. No signal is observed and limits on the branching fractions B ( t → H c ) < 0.16 % and B ( t → H u ) < 0.19 % at 95% confidence level are obtained (with expected limits of 0.15% in both cases).

U2 - 10.1103/PhysRevD.98.032002

DO - 10.1103/PhysRevD.98.032002

M3 - Journal article

VL - 98

JO - Physical Review D

JF - Physical Review D

SN - 1550-7998

IS - 3

M1 - 032002

ER -