Electron-positron pair creation with capture and ionization in relativistic heavy-ion collisions by the finite-difference method

The probabilities of electron-positron pair creation with K-shell capture, of ionization, and of excitation are nonperturbatively calculated with a finite-difference method. Calculations for a collision of ${\mathrm{U}}^{92+}$ on ${\mathrm{U}}^{91+}$ at ${\mathit{E}}_{\mathrm{lab}}$=10 GeV/nucleon at small impact parameters are presented. The results show an enhancement of the probability for pair creation with the capture of about two orders of magnitude in comparison to the outcome of a calculation in first-order perturbation theory. This proves the expected strong nonperturbative character of such relativistic collisions for very heavy ions.