Production of charmonia by recombination in heavy ion collisions

We study the production of charmonium states in heavy ion collisions by focusing on their production by recombination of charm and anticharm quarks in a quark-gluon plasma. Starting from the discussion on Wigner functions for charmonium states we investigate the dependence of charmonia production on their wave functions. We show that the transverse momentum distribution of charmonium states strongly reflects their wave function distributions in momentum space, providing a plausible explanation for the recent measurement of the nuclear modification factor ratio between the ψ(2S) and J/ψ meson.