Subthreshold antiproton production in proton-carbon reactions

Data from KEK on subthreshold (p) over bar as well as on π^± and K^± production in proton-nucleus reactions are described at projectile energies between 3.5 and 12.0 GeV. We use a model which considers a hadron-nucleus reaction as an incoherent sum over collisions of the projectile with a varying number of target nucleons. It samples complete events and thus allows for the simultaneous consideration of ail particle species measured. The overall reproduction of the data is quite satisfactory. It is shown that the contributions from the interaction of the projectile with groups of several target nucleons are decisive for the description of subthreshold production. Since the collective features of subthreshold production become especially significant far below the threshold, the results are extrapolated down to COSY energies. It is concluded that an p measurement at ANKE-COSY should be feasible, if the high background of other particles can be efficiently suppressed.