  Using a multiphase transport model, we study the relative importance of J/psi
suppression mechanisms due to plasma screening, gluon scattering, and hadron
absorption in heavy ion collisions at the Relativistic Heavy Ion Collider. We
find that for collisions between heavy nuclei such as Au+Au, both plasma
screening and gluon scattering are important. As a result, the effect due to
absorption by hadrons becomes relatively minor. The final J/psi survival
probability in these collisions is only a few percent. In the case of
collisions between light nuclei such as S+S, the effect of plasma screening is,
however, negligible in spite of the initial high parton density. The final
J/psi survival probability thus remains appreciable after comparable absorption
effects due to gluons and hadrons.
