Enhancement of Intermediate Mass Dileptons From Charm Decays At SPS Energies

We study the dimuon yield from open charm decays in the intermediate mass region(IMR) in heavy-ion collisions at the CERN-SPS energy. We find that final state rescatterings which broaden the mT spectrum of charmed mesons can enrich the part of the phase space covered by the NA50 experiment, thus leading to an apparent enhancement of IMR dileptons within the acceptance of the experiment. Such an enhancement increases with the dimuon invariant mass and the single muon energy cut-off. Dileptons are important signals in high-energy heavy-ion collisions. Depending on their invariant masses they can probe the collision processes at different stages. Low invariantmass dileptons are predominantly produced at the late stage of the collisions. So they provide information about the medium modification of hadron properties such as mass and spectral functions [1,2]. A large enhancement of low invariant-mass dileptons has indeed been