Strong Suppression of Coulomb Corrections to the e+e– Pair Production Cross Section in Ultrarelativistic Nuclear Collisions1

摘要

The Coulomb corrections to the e+e– pair production cross section in ultrarelativistic nuclear col lisions are calculated in the nexttoleading approximation with respect to the parameter L = lnγAγB, where γA, B are the Lorentz factors of colliding nuclei. We find considerable reduction of the Coulomb corrections even for large γAγB due to the suppression of the e+e– pair production with the total energy of the order of a few electron masses in the rest frame of one of the nuclei. Our result explains why the deviation from the Born result was not observed in the SPS experiment [1, 2].