Nuclear Stopping Power Evaluated Via Free Protons Emitted In Reaction Xe Plus Sn Near Fermi Energy

The dissipation phenomenon has been studied by simulating the reaction Xe-129+(129) Sn with Isospin-dependent Quantum Molecular Dynamics ( IQMD) model. The evolution of the isotropic ratio with bombarding energy for the free protons moving forward in the center of mass system in the final state of the reactions, drawn from the experimental measurements by INDRA collaboration, is reproduced with the model in the energy region near and slightly higher than the Fermi energy. Comparison of the data with the simulation obtained using the IQMD model in the cases of different combinations of in-medium effects in two-body collisions, i.e., medium modification of nucleon-nucleon cross-section and Pauli-blocking effect, indicates that the Pauli exclusion principle is indispensable in the microscopic model and the Pauli-blocking in binary interactions dominates the in-medium effects in the heavy-ion reactions in the energy range, even below the Fermi energy. Based on such comparisons, an energy-dependent effective factor responsible for the Pauli-blocking in the binary collisions in heavy-ion collisions in the Fermi energy domain has been extracted.