Heavy quark correlations and the effective volume for quarkonia production
Using the Boltzmann transport approach, we study the effective volume of a correlated heavy quark pair in a partonic medium based on their collision rate. We find that the e ffective volume is finite and depends sensitively on the momentum of the heavy quark and the temperature of the medium. Generally, it increases linearly with time t at the very beginning and the increase then becomes slower due to multiple scattering, and finally it increases linearly with respect to t 3/2 . We further find that the colliding heavy quark pair has an e ffective temperature similar to that of the