Аннотация:Lepton-pairs production in hadron-hadron collisions is considered in the framework of the parton model with transverse motion of the partons. Owing to the parton transverse momenta, annihilation of a quark and an antiquark from the same hadron is possible. This new mechanism should dominate at large longitudinal momenta and small values of the parameter tau of the lepton pair. The distribution functions of quarks and quark-antiquark pairs are calculated using the modified Kuti-Weisskopf model. It is shown that it is possible to reproduce the experimental data on production of low-mass muon pairs below the rho-meson peak by increasing the level of sea quarks in the proton. In this case the sea quarks should carry about 80% of the proton momentum.