2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/185664We calculate the probability of electron-positron pair creation in vacuum in 3+1 dimensions by an external electromagnetic field composed of a constant uniform electric field and a constant uniform magnetic field, both of arbitrary magnitudes and directions. The same problem is also studied in 2+1 and 1+1 dimensions in appropriate external fields and similar results are obtained.REVTeX, 10 pages, no figure, a brief note and some more references added in the proofHigh Energy Physics - Theorytext