Rapid thermalization in ultra-relativistic heavy-ion collisions leads to fast
changing potential between a heavy quark and antiquark from zero temperature
potential to the finite temperature one. Time dependent perturbation theory can
then be used to calculate the survival probability of the initial quarkonium
state. In view of very short time scales of thermalization at RHIC and LHC
energies, we calculate the survival probability of J/ψ and Υ
using sudden approximation. Our results show that quarkonium decay may be
significant even when temperature of QGP remains low enough so that the
conventional quarkonium melting due to Debye screening is ineffective.Comment: 3 pages, 4 figure