Possibility of charmoniumlike state $X(3915)$ as ${\chi }_{c0}(2P)$ state

Abstract

In this work, we seriously discuss whether $X(3915)$ can be treated as a ${\chi }_{c0}(2P)$ state. Based on an unquenched quark model, we give the mass spectrum of the ${\chi }_{cJ}(2P)$ states, where there are no free input parameters in our calculation. Our result shows that the mass gap between ${\chi }_{c0}(2P)$ and ${\chi }_{c2}(2P)$ can reach 13 MeV, which can reproduce the mass difference between $Z(3930)$ and $X(3915)$. Additionally, the calculated masses of ${\chi }_{c0}(2P)$ and ${\chi }_{c2}(2P)$ are consistent with experimental values of $X(3915)$ and $Z(3930)$, respectively. Besides, giving the mass spectrum analysis to support $X(3915)$ as ${\chi }_{c0}(2P)$, we also calculate the width of ${\chi }_{c0}(2P)$ with the same framework, which is also consistent with the experimental data of $X(3915)$. Thus, the possibility of charmoniumlike state $X(3915)$ as ${\chi }_{c0}(2P)$ state is further enforced.

Comments: 12 pages, 9 figures and 6 tables. More discussions added. Accepted by PRD for publication