Thermal dilepton and open charm signals versus hard initial yields in heavy-ion collisions at RHIC and LHC energies

The hard initial production of open charm and dileptons is compared with possible thermal signals in heavy-ion collisions at RHIC and LHC energies. Our approach is based on the perturbative QCD mini-jet mechanism of quark-gluon matter formation. The thermal dilepton signal is found to rise much stronger as compared to the hard Drell-Yan background with increasing collider energy and clearly dominates at LHC energy. Oppositely, open charm stems from initial hard production. A possible manifestation of gluon shadowing at RHIC and LHC energies is discussed.