Search for Rare Decays of Z and Higgs Bosons to J/ψ and a Photon in Proton-Proton Collisions at √s = 13 TeV
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Sirunyan2019_Article_SearchForRareDecaysOfMathrmZZA.pdf
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Author(s)
CMS Collaboration
Abercrombie, Daniel Robert
Allen, Brandon Leigh
Azzolini, Virginia
Baty, Austin Alan
Bauer, Gerry P
Bi, Ran
Brandt, Stephanie Akemi
Busza, Wit
Cali, Ivan Amos
Date Issued
January 2019
Journal
European Physical Journal C: Particles and Fields
Publisher
Springer-Verlag
Citation
Sirunyan, A. M. et al. “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 79, 2 (January 2019): 94 © 2019 CERN for the benefit of the CMS collaboration
Version
Final published version
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 = 13 TeV 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 = 8 TeV 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.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1140/epjc/s10052-019-6562-5
