Comparison of the soft-annihilation model of low-mass dilepton production with the data

Data on low-mass lepton pair production in hadron collisions are systematically compared with the predictions of the soft-annihilation model. In this model, lepton pairs are originated by the annihilations of quarks and antiquarks created during the collision. The surprisingly good qualitative and sometimes quantitative agreement indicates that this mechanism dominates the low-mass lepton pair production. Only further data on very-low-mass $e^{+}{e}^{-}$ production can provide information about the relative amounts of soft subprocesses $q\overline{q}\to l^{+}{l}^{-}$ and $q\overline{q}\to l^{+}{l}^{-}+X$ (such as $q\overline{q}\to l^{+}{l}^{-}$ + gluon).