e+e− yields in Pb+Au collisions at 158 A GeV/c: assessment of baryonic contributions

Using a hydrodynamic approach to describe Pb+Au collisions at 158 A GeV/c, we analyze e+e− yields from matter containing baryons in addition to mesons. We employ e+e− production rates from two independent calculations, which differ both in their input physics and in their absolute magnitudes, especially in the mass range where significant enhancements over expected backgrounds exist in the CERES data. Although the presence of baryons leads to significant enhancement of e+e− emission relative to that from mesons-only matter, the calculated results fall below the data in the range 400