TY  - JOUR
AU  - ATLAS Collaboration (Aaboud, M. et al
AU  - Alvarez Piqueras, D.
AU  - Aparisi Pozo, J. A.
AU  - Bailey, A. J.
AU  - Barranco Navarro, L.
AU  - Cabrera Urban, S.
AU  - Castillo, F. L.
AU  - Castillo Gimenez, V.
AU  - Cerda Alberich, L.
AU  - Costa, M. J.
AU  - Escobar, C.
AU  - Estrada Pastor, O.
AU  - Ferrer, A.
AU  - Fiorini, L.
AU  - Fullana Torregrosa, E.
AU  - Fuster, J.
AU  - Garcia, C.
AU  - Garcia Navarro, J. E.
AU  - Gonzalez de la Hoz, S.
AU  - Higon-Rodriguez, E.
AU  - Jimenez Pena, J.
AU  - Lacasta, C.
AU  - Lozano Bahilo, J. J.
AU  - Madaffari, D.
AU  - Mamuzic, J.
AU  - Marti-Garcia, S.
AU  - Melini, D.
AU  - Miñano, M.
AU  - Mitsou, V. A.
AU  - Rodriguez Bosca, S.
AU  - Rodriguez Rodriguez, D.
AU  - Ruiz-Martinez, A.
AU  - Salt, J.
AU  - Santra, A.
AU  - Soldevila, U.
AU  - Sanchez, J.
AU  - Valero, A.
AU  - Valls Ferrer, J. A.
AU  - Vos, M.
PY  - 2019
DA  - 2019//
TI  - Search for top-quark decays t -> Hq with 36 fb(-1) of pp collision data at root s=13 TeV with the ATLAS detector
T2  - J. High Energy Phys.
JO  - Journal of High Energy Physics
SP  - 123
EP  - 67pp
VL  - 05
IS  - 5
PB  - Springer
KW  - Hadron-Hadron scattering (experiments)
KW  - Rare decay
KW  - Top physics
AB  - A search for flavour-changing neutral current decays of a top quark into an up-type quark (q = u, c) and the Standard Model Higgs boson, t Hq, is presented. The search is based on a dataset of pp collisions at = 13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 36.1 fb(-1). Two complementary analyses are performed to search for top-quark pair events in which one top quark decays into Wb and the other top quark decays into Hq, and target the Hbb and H (+-) decay modes, respectively. The high multiplicity of b-quark jets, or the presence of hadronically decaying -leptons, is exploited in the two analyses respectively. Multivariate techniques are used to separate the signal from the background, which is dominated by top-quark pair production. No significant excess of events above the background expectation is found, and 95% CL upper limits on the t Hq branching ratios are derived. The combination of these searches with ATLAS searches in diphoton and multilepton final states yields observed (expected) 95% CL upper limits on the t Hc and t Hu branching ratios of 1.1 x 10(-3) (8.3 x 10(-4)) and 1.2 x 10(-3) (8.3 x 10(-4)), respectively. The corresponding combined observed (expected) upper limits on the |(tcH)| and |(tuH)| couplings are 0.064 (0.055) and 0.066 (0.055), respectively.
SN  - 1029-8479
UR  - https://arxiv.org/abs/1812.11568
UR  - https://doi.org/10.1007/JHEP05(2019)123
DO  - 10.1007/JHEP05(2019)123
LA  - English
N1  - WOS:000468948900001
ID  - ATLASCollaborationAaboud_etal2019
ER  -