Cross section and parametrization of charmonium decay

The parametrization forms of charmonium quasi two body decays are discussed in detail in this paper. The symmetry analysis and magnetic transition description are utilized to provide the multi-aspect comprehension of the decay dynamics, including the meson mixing angle, form factor, and $SU(3)$ symmetry breading effect. As the prerequisite, the electromagnetic cross sections involving scalar and pseudoscalar, are calculated for eight final states based on the approach of current algebra. Moreover, the mathematical manipulations of calculation for four kinds of final states are spelled out to illuminate the technique strategy.