Gluon mass from charmonium radiative decay and its impact on the hybrid meson properties

We study the photon spectrum in the radiative decays of the charmonium $\frac{1}{\mathrm{\Gamma }}\frac{d\mathrm{\Gamma }(J\mathrm{/}\psi \to \gamma gg)}{dz}$ as an excellent scene for hunting the exotic mesons (hybrids $q\bar{q}g$ and glueballs $gg$) and an ideal frame for the theoretical and phenomenological investigations of the gluon nature in IR, by subtle estimation of its non-zero effective mass which seems required in Quark-Gluon Constituent Model (QGCM) for identifying the nature of these exotic species.