Feynman--Monte Carlo calculations of electron capture at relativistic collider energies

Calculations are presented for electron capture associated with pair production in collisions of heavy ions at relativistic energies. We employ the recently introduced technique of evaluating Feynman perturbation integrals exactly by Monte Carlo methods. The results agree well with virtual-photon approximations if they are carefully formulated, but appear to disagree with some published results. The cross sections for symmetric collisions of uranium, gold, iodine, copper, and silicon are presented as a function of the beam energy. These results are discussed within the context of beam storage times of a relativistic heavy-ion collider