ELECTRON-POSITRON PAIR PRODUCTION IN COULOMB COLLISIONS BY 6.4-TEV SULFUR IONS

Angular and momentum distributions have been measured for electron-pos itron pairs created in peripheral collisions of 6.4-TeV bare sulfur io ns with thin targets of Al, Pd, and Au. Singly and doubly differential cross sections are presented for 1-17 MeV/c electrons and positrons d etected independently and in coincidence as pairs. Integrated yields f or pair production are found to vary as the square of the target nucle ar charge. Relative angular and momentum differential cross sections a re effectively target independent. Various physical parameters are ded uced from the coincident electron and positron data, including probabi lity distributions for the pair transverse momentum, the pair total en ergy, and the positron fraction of the pair energy. Where possible, re sults of these measurements are compared with theory.