REANALYSIS OF ANTIPROTON PRODUCTION IN PROTON-NUCLEUS AND NUCLEUS-NUCLEUS REACTIONS AT SUBTHRESHOLD ENERGIES

We reanalyse the production of p (p) over bar pairs in proton-nucleus and nucleus-nucleus collisions employing novel elementary cross sectio ns for baryon-baryon and pion-baryon production channels based on a bo son-exchange model. In contrast to previous transport studies performe d in the literature the secondary pion induced channel is found to be most important in both p + A and A + A collisions at subthreshold ener gies. A detailed comparison with the experimental data available indic ates that sizeable attractive (p) over bar potentials in the order of -100 to -150 MeV at normal nuclear matter density are needed to reprod uce the size and shape of the experimental spectra. (C) 1998 Elsevier Science B.V.