EXCESS DILEPTONS IN HIGH-ENERGY NUCLEUS-NUCLEUS COLLISIONS

It has been observed recently that while continuum dilepton production and open charm production in high-energy pA collisions can be describ ed in terms of the superposition of pp collisions, dilepton yields in S+U collisions are in excess of similar extrapolations. This feature c an be explained as arising from the interaction of gluons produced in different soft baryon-baryon collisions, leading to additional open-ch arm pairs in nucleus-nucleus collisions but not in pA collisions.