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


Sirunyan A. M., Tumasyan A., Adam W., Ambrogi F., Asilar E., Bergauer T., ...Daha Fazla

European Physical Journal C, cilt.79, sa.2, 2019 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 79 Sayı: 2
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1140/epjc/s10052-019-6562-5
  • Dergi Adı: European Physical Journal C
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • İstanbul Üniversitesi Adresli: Evet

Özet

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.