Search for Rare Decays of Z and Higgs Bosons to J/ψ and a Photon in Proton-Proton Collisions at √s = 13 TeV
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; D'Alfonso, Mariarosaria; Demiragli, Zeynep; Gomez-Ceballos, Guillelmo; Goncharov, Maxim; Harris, Philip Coleman; Hsu, Dylan George; Hu, Miao; Iiyama, Yutaro; Innocenti, Gian Michele; Klute, Markus; Kovalskyi, Dmytro; Lee, Yen-Jie; Luckey Jr, P David; Maier, Benedikt; Marini, Andrea Carlo; McGinn, Christopher Francis; Mironov, Camelia Maria; Narayanan, Siddharth Madhavan; Niu, Xinmei; Paus, Christoph M. E.; Roland, Christof E; Roland, Gunther M; Stephans, George S. F.; Sumorok, Konstanty C; Tatar, Kaya; Velicanu, Dragos Alexandru; Wang, Jing; Wang, Ta-Wei; Wyslouch, Boleslaw; Shi, Zhaozhong; ... Show more Show less
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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.
DepartmentMassachusetts Institute of Technology. Department of Nuclear Science and Engineering; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science
European Physical Journal C: Particles and Fields
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
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