Strong decays allowed by the Okubo-Zweig-Iizuka rule play a decisive role in determining the properties of particles. The widely used $^{ 3}P_{ 0}$ model is non-relativistic and contains unknown adjustable parameter $\gamma$ that need to be determined experimentally. Based on the Bethe-Salpeter equation, we have derived a relativistic calculation formula without additional parameters similar to $\gamma$. Using this method, we present the total width of $h_{ c}(2P)$ and theoretically determine the value of the parameter $\gamma$ in the $^{ 3}P_{ 0}$ model.
Categories: hep-ph