Search for rare decays of Z and Higgs bosons to J / ψ and a photon in proton-proton collisions at s = 13 TeV.

Abstract

A search is presented for decays of Z and Higgs bosons to a J/ meson and a photon, with the subsequent decay of the J/ to +-. The analysis uses data from proton-proton collisions with an integrated luminosity of 35.9fb-1 at =13collected with the CMS detector at the LHC. The observed limit on the ZJ/ decay branching fraction, assuming that the J/ meson is produced unpolarized, is 1.4x10-6 at 95% confidence level, which corresponds to a rate higher than expected in the standard model by a factor of 15. For extreme-polarization scenarios, the observed limit changes from -13.6 to +8.6% with respect to the unpolarized scenario. The observed upper limit on the branching fraction for HJ/ where the J/ meson is assumed to be transversely polarized is 7.6x10-4, a factor of 260 larger than the standard model prediction. The results for the Higgs boson are combined with previous data from proton-proton collisions at =8TeV to produce an observed upper limit on the branching fraction for HJ/ that is a factor of 220 larger than the standard model value.Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu: MDM-2015-0509Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de MaeztuFonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium)Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University (Thailand)Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand)Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences (Hungary)FWO (Belgium) under the Excellence of Science - EOS - be.h project: 30820817Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium)Mobility Plus program of the Ministry of Science and Higher Education