Quark exchange model for charmonium dissociation in hot hadronic matter

A diagrammatic approach to quark exchange processes in meson-meson scattering is applied to the case of inelastic reactions of the type $(Q\text{barQ})+(q\text{barq})\to (Q\text{barq})+(q\text{barQ})$, where $Q$ and $q$ refer to heavy and light quarks, respectively. This string-flip process is discussed as a microscopic mechanism for charmonium dissociation (absorption) in hadronic matter. The cross section for the reaction $J\mathrm{/}\psi +\pi \to D+\bar{D}$ is calculated using a potential model, which is fitted to the meson mass spectrum. The temperature dependence of the relaxation time for the $\text{J}\mathrm{/}Psi$ distribution in a homogeneous thermal pion gas is obtained. The use of charmonium for the diagnostics of the state of hot hadronic matter produced in ultrarelativistic nucleus-nucleus collisions is discussed.