ANTIPROTON PRODUCTION IN P+D REACTION AT SUBTHRESHOLD ENERGIES

An enhancement of antiprotons produced in the p + d reaction in compar ison over those produced in the p + p elementary reaction is investiga ted. In the neighborhood of the subthreshold energy, the enhancement i s caused by tl:le difference in threshold energies for antiproton prod uction. The cross section of the p + d reaction, on the other hand, be comes just twice that in the elementary p + p reaction at the incident energy far from the threshold energy when non-nucleon components in t he deuteron target are not considered.