Charmonium: Conventional and $XYZ$ States in a Relativistic Screened Potential Model

In this work a comprehensive analysis of the mass spectrum and decay properties of charmonium states within a relativistic framework is carried out. The present experimental status of charmonium states is reviewed. Utilizing a screened potential model, we compute the spectra and various decay widths for $c\bar{c}$ bound system, comparing our results with experimental data and existing theoretical models. We calculate the decay constants, $E1$ and $M1$ transitions, and annihilation decay widths, confirming the consistency of our model with experimental observations for well-established charmonium states. The interpretation of charmonium-like states, $X(4140)$, $X(4274)$, and $X(4500)$ as $P$ wave charmonium states and $\psi (4040)$, $\psi (3770)$, $\psi (4160)$, $\psi (4230)$, $\psi (4360)$, $\psi (4415)$, $Y(4500)$ and $Y(4360)$ as $S-D$ mixed charmonium states are carried out.