Search

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

The newly observed ${\mathrm{\ensuremath{\Sigma}}}_{b}(6097)$ provides us a good chance to further construct the high excited states of the bottom baryon family. In this work, we explain the ${\mathrm{\ensuremath{\Sigma}}}_{b}(6097)$ to be a $1P$ state with ${J}^{P}=5/{2}^{\ensuremath{-}}$ or $3/{2}^{\ensuremath{-}}$ by giving the mass spectrum analysis and the strong decay calculation, and predict the existence of $1P$ and $2S$ partners of the ${\mathrm{\ensuremath{\Sigma}}}_{b}(6097)$, where their masses and the corresponding decay behaviors are presented. Because of the success of describing the ${\mathrm{\ensuremath{\Sigma}}}_{b}(6097)$ and the former observed ${\mathrm{\ensuremath{\Xi}}}_{b}(6227)$ under the quasi-two-body treatment to the bottom baryons, we continue to predict the ${\mathrm{\ensuremath{\Omega}}}_{b}$ partners of ${\mathrm{\ensuremath{\Sigma}}}_{b}(6097)$ by the same method, which are the $1P$ and $2S$ states of the $bss$ baryon system. Identifying these predicted bottom baryons will be a research topic full of challenge and opportunity for future experiments, especially the LHCb.

Selecting the newly observed ${\mathrm{\ensuremath{\Xi}}}_{b}(6227{)}^{\ensuremath{-}}$ by LHCb as a study example, we decode its inner structure by giving the mass spectrum analysis and the investigation of its two-body strong decay behaviors. Our result indicates that the ${\mathrm{\ensuremath{\Xi}}}_{b}(6227{)}^{\ensuremath{-}}$ is a good candidate of the $P$-wave ${\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{'}}$ state with ${J}^{P}=3/{2}^{\ensuremath{-}}$ or $5/{2}^{\ensuremath{-}}$. In addition, we further provide the information of the properties of the partners of the ${\mathrm{\ensuremath{\Xi}}}_{b}(6227{)}^{\ensuremath{-}}$. These predicted states include three $2S$ states and the remaining $1P$ states in the bottom-strange baryon family. The calculated sizable Okubo-Zweig-Iizuka--allowed decay widths of these partners show that the experimental search for them becomes possible via LHCb. We have a reason to believe that the present study can be treated as a start point for constructing the highly excited bottom baryon spectroscopy.