本篇論文目的為尋找Z玻色子和希格斯玻色子衰變至一個J/ψ介子和一個光子的頻道，其中J/ψ介子進一步衰變至渺子對 (μ+μ−)。此分析使用於2016年由大型強子對撞機 (LHC)產生的質子對撞，質心能量為13兆電子伏特 (TeV)，並由緊湊緲子線圈 (CMS) 所收集，對應於總光度35.9飛靶 (inverse femto-barn)之事件。若J/ψ介子不帶極性，在95%信心水準下，Z玻色子衰變頻道之衰變分支比例的觀測上限為1.4×10−6，約對應至15倍的標準模型預測值。假設J/ψ介子帶有縱向或橫向極性，衰變分支比例的觀測上限對應於不帶極性之假設有-13.6至+8.6%的差異。在J/ψ介子帶有橫向極性且在95%信心水準下，希格斯玻色子衰變頻道之衰變分支比例的觀測上限為7.6×10−4，約對應至260倍的標準模型預測值。在統計上，此希格斯玻色子衰變頻道之結果與由質心能量8兆電子伏特所得到之結果合併計算，得到衰變分支比例的觀測上限約對應至220倍的標準模型預測值。;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 35.9 fb−1 at √s = 13 TeV collected with the CMS detector at the LHC. The observed limit on the Z→J/ψ γ 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/ψ γ 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/ψ γ that is a factor of 220 larger than the standard model value.
