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

Autori
Sirunyan, Albert ; ... ; Đurić, Senka ; Lelas, Damir ; Godinović, Nikola ; Puljak, Ivica ; Šćulac, Toni ; Mesić, Benjamin ; Šuša, Tatjana ; Kovač, Marko ; Ferenček, Dinko ; Antunović, Željko ; Starodumov, Andrey ; Brigljević, Vuko ; Luetić, Jelena ; Kadija, Krešo ; ... ; Woods, Nate

Kolaboracija
CMS Collaboration

Izvornik
European physical journal C : particles and fields (1434-6044) 79 (2019), 2; 94, 27

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
High energy physics, Experimental particle physics, LHC, CMS, Standard Model

Sažetak
A search is presented for decays of Z and Higgs bosons to a J/ψ meson and a photon, with the subsequent decay of the J/ψ to μ+μ−. The analysis uses data from proton-proton collisions with an integrated luminosity of 35.9fb−1 at s√=13TeV collected with the CMS detector at the LHC. The observed limit on the Z→J/ψγ decay branching fraction, assuming that the J/ψ meson is produced unpolarized, is 1.4×10−6 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 H→J/ψγ where the J/ψ meson is assumed to be transversely polarized is 7.6×10−4, 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 s√=8TeV to produce an observed upper limit on the branching fraction for H→J/ψγ that is a factor of 220 larger than the standard model value.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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