中国物理学会高能物理分会第十一届全国会员代表大会暨学术年会

We study the hot-medium effects on charmonium. Previously most work were focused on the medium effects on the gluon propagator of the charmonium, but ignored that on the $c$ quark and $\bar{c}$ anti-quark. However, the hot medium interacts with not only gluons but also quarks. Here we study the hot-medium effects on both $c,\bar{c}$ and the transferred gluon based on two-particle fractal model. We analyze the probability and entropy of the charmonium from quark and charmonium aspects. We solve the probability and entropy equations and obtain the medium influencing factor $q_{gQ}$ and $q_Q$. The factor $q_{gQ}$ and $q_{Q}$ reflect medium effects on gluons and heavy quarks and on heavy quarks respectively. It is found $q_{gQ}$ and $q_Q$ are both more than 1. This implies that the hot medium influence both the transferred gluon and heavy quarks. When increasing the temperature $q_{gQ}$ and $q_{Q}$ are found to deviate more from $1$. This illustrates the hot medium influence charmonium more at higher temperature. We calculate the value of $q_{gQ}$ at critical temperature and obtain the transverse momentum spectrum of $J/\psi$. Our result shows a good agreement with the experimental data. The two-particle fractal model can be used to study other mesons and tetraquark system in the future.