Secondary Drell–Yan dileptons in heavy-ion reactions

We investigate the contribution of partonic interactions between incident nucleons and produced mesons to the dilepton continuum in heavy-ion reactions. A schematic model is employed in order to calculate the resulting Drell–Yan yield as a function of collision energy and for different scenarios concerning the formation of hadrons. The secondary Drell–Yan process is found to be significant for invariant masses [Formula: see text][Formula: see text]GeV in central [Formula: see text] collisions around [Formula: see text][Formula: see text]GeV, but less so at much lower or much higher energies. Secondary Drell–Yan dileptons should be observable in experiments due to their distinct rapidity dependence as a characteristic deviation from the well-known (primary) Drell–Yan contribution due to [Formula: see text] interactions. The predicted strong dependence of the secondary Drell–Yan contribution on the nuclear collision energy can be used to experimentally probe the effective hadronic formation time of secondaries.