Centrality dependence of antiproton production in Proton-Nucleus Collisions at 17.5 and 12.3 GeV

Experiment 910, performed at the Brookhaven National Laboratory Alternating Gradient Synchrotron (BNL-AGS), is a fixed target proton-nucleus experiment. We analyze data for nominal beam momenta 12 GeV/c and 18 GeV/c and targets Au, Cu, and Be. We characterize events with the number of projectile collisions. A new model is presented to relate the number of "grey tracks"to the number of projectile collisions and compared to a previously established model. The results of the models are similar, but the new model is shown to better describe the data. We investigate antiproton production. In an attempt to disentangle the production mechanisms and reabsorption of antiprotons within the nucleus, yields of antiproton production are compared for different targets and beam momenta. For the first time, antiproton multiplicities are investigated as a function of the number of projectile collisions. Results show that the mean antiproton multiplicities tend to decrease with increasing number of projectile collisions. We compare results with cascade model predictions.