Hadronic sources of dileptons from heavy ion collisions at intermediate and relativistic energies

The kinetic model developed previously for soft hadron-nucleus and nucleus-nucleus collisions has been extended to describe low mass dilepton production. A version of the quark-gluon string model is used to get an input information on unstable particles produced in hadron-hadron collisions. Taking into account a variety of e+e- sources, a fairly good description of available experimental data on dileptons created in both, p + Be collisions from 12 to 1 GeV and Ca+Ca collisons at the energies 2 and 1 GeV/nucleon, is attained. Confirming a previous estimate of the ππ annihilation process, it has been found that the ω/ρ → e +e- decay contributes as much as ππ annihilation does and into the same region of invariant masses, even for Ca+Ca (1 GeV/nucleon) collisions. (orig.)