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 (QQ{})+(qq{}){→}(Qq{})+(qQ{}), 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/{ψ}+{π}{→}D+D{} is calculated using a potential model, which is fitted to the meson mass spectrum. The temperature dependence of the relaxation time for the J/{ψ} 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.