Proton distributions in the target fragmentation region in proton - nucleus and nucleus-nucleus collisions at high-energies

We present measurements of the rapidity and transverse-momentum distributions of the protons emitted in S + W, O + W, and p + W reactions at 200 GeV/A around the target rapidity (y = 1). The rapidity density rises linearly with the transverse energy for all three systems, but the slope for p + W is much steeper than for O + W and S + W. The rapidity density for p + W is much higher than predicted by summing single nucleon-nucleon collisions without any nuclear effects, indicating substantial rescattering of the produced particles. The predictions of the VENUS 3 model, including rescattering, show reasonable agreement with the data for all three systems. We do not have evidence for a strong collective flow of the outgoing particles.