The rapidity distributions of protons produced in Au--Au collisions at the Alternating Gradient Synchrotron (AGS) energies are investigated by a two-cylinder model. The different distribution shapes for different centrality cuts are mainly determined by different contributions of leading protons. The cylinders contribute the same distribution shape for different centrality cuts. The calculated results are compared and found to be in agreement with the experimental data of the E917 Collaboration.

PACS numbers: 25.75.--q, 24.10.Pa