  Assuming the Statistical Hadronization Model and charm flavour conservation,
one can quantify the deviation of charm and anti-charm quarks from chemical
equilibrium both in the hadronic phase and in the quark-gluon plasma. By
linking the hadronic fireball volume and the corresponding plasma source volume
via entropy conservation as proposed by Grandchamp et al., a direct comparison
between the $J/\psi$ yields in both pictures can be used to obtain limits for
the charm quark mass in the medium.
