Mott effect at the chiral phase transition and anomalous J/ψ suppression

We investigate the in-medium modification of the charmonium break-up process due to the Mott effect for light (π) and open-charm (D, D∗) mesons at the chiral/deconfinement phase transition. A model calculation for the process J/ψ+π→D+D̄∗+h.c. is presented which demonstrates that the Mott effect for the D-mesons leads to a threshold effect in the thermal averaged break-up cross section. This effect is suggested as an explanation of the phenomenon of anomalous J/ψ suppression in the CERN NA50 experiment.