Structure of the Coulomb and unitarity corrections to the cross section of e+e- pair production in ultrarelativistic nuclear collisions

We analyze the structure of the Coulomb and unitarity corrections to the single e+e- pair production, as well as the cross section σn for the multiple pair production in collision of ultra-relativistic nuclei. In the external field approximation, we consider the probability of one pair production at a fixed impact parameter ρ between colliding nuclei. We obtain the analytical result for this probability at large ρ as compared to the electron Compton wavelength. The energy dependence of this probability, as well as that of σn, differ essentially from widely cited but incorrect results. We estimate also the unitary corrections to the total cross section of the process