The Study Of Heavy Quarkonia Of Electromagnetic Radiative Decay

We systematically study the electromagnetic transitions of the nS,nP(n ≤3), and nD(n ≤ 2) charmonium states and bottomonium states with a constituent quark model. In our caculations, we obtain a reasonable description of the electromagnetic transitions of the well-established low-lying charmonium states J/ψ,ψ(2S), χcJ(1P), hc(1P) and ψ(3770). Our predictions of electromagnetic decay properties for the higher charmonium states are also presented and compared with other model predictions. In particular, we analyzed the radiative transition process of some “XY Z” state as Charmonium state,such as X(3823)、X(3872)、X(3915)、X(3940) and X(4315). Considering the X(3872)resonance as the χc1(2P) state, we study its electromagnetic decay properties. Our predicted ratio Γ[X(3872) �' ψ(2S)γ]/Γ[X(3872) �' J/ψγ] which value is ～ 15.0,it’s different from experimental measurements obviously. Our theoretical model does not support the X(3872) as a candidate of χc1(2P) from this branching rate.On this basis, we further studied bottomonium system which has lower relativistic effects.We obtain some reasonable description of the measured decay rates,but we can also find that some of our predictions are notably different from those of other models. In our calculations, we found that some of the E1 transitions dominant radiative decay process, interference effects between E1 and M2 transitions will produce significant correction to results. We hope our study could provide some useful references to observe the EM radiative transitions between heavy-quarknium states in forthcoming experiments.