Charmonium production from hot hadronic matter

Charmonium production from DD̄ annihilation in the hadron gas formed in ultra-relativistic heavy-ion collisions is studied. With initial conditions taken from the HIJING parton model, we have estimated the number of J/ψ produced from an expanding hadron gas, using the J/ψ absorption and production cross sections obtained from either an effective Lagrangian or the quark-exchange model. We find that J/ψ production is negligible in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) but may be important at the Large Hadron Collider (LHC), where more charm mesons are produced. Similar results are obtained for ψ′ production from the hadron gas at RHIC and LHC.