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.

Sirunyan, A.M., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., et al. (2019). Search for rare decays of Z and Higgs bosons to J / ψ and a photon in proton-proton collisions at √s = 13 TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 79(2), 1-27 [10.1140/epjc/s10052-019-6562-5].

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

Battilana C.;Bonacorsi D.;Borgonovi L.;Braibant-Giacomelli S.;Campanini R.;Capiluppi P.;Castro A.;Chhibra S. S.;Codispoti G.;Cuffiani M.;Fanfani A.;Fontanesi E.;Guiducci L.;Iemmi F.;Navarria F. L.;Primavera F.;Rovelli T.;Siroli G. P.;
2019

Abstract

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.
2019
Sirunyan, A.M., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., et al. (2019). Search for rare decays of Z and Higgs bosons to J / ψ and a photon in proton-proton collisions at √s = 13 TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 79(2), 1-27 [10.1140/epjc/s10052-019-6562-5].
Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Dragicevic, M.; Ero, J.; Del Valle, A. E.; Flechl, M...espandi
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