Higher-order effects on pair creation by relativistic heavy-ion beams

Assuming the approximation of pair independence, the number of pairs produced by a classical, imperturbable electromagnetic source is shown to be described by a Poisson distribution. The perturbational calculation of pairs by colliding heavy-ion beams is treated by straightforward summation of the diagrammatically defined series. The extended calculation, in which all orders of interaction between colliding ions and the electron-positron system are included, is also demonstrated to result in a Poisson-number distribution. Applications to current heavy-ion colliders are made.