Heavy-ion fusion cross sections in the barrier and high-energy regions: Signature of energy dependence in the repulsive core potential

The effect of incompressibility of cold nuclear matter (CNM) on the high-energy fusion data of the Mg-26+Cm-248, S-36+U-238, Ca-48+Pb-208, Ti-50+Bi-209 and Ca-40(,)48+U-238 colliding systems with 1152 <= Z(1)Z(2) <= 1840 has been analyzed using coupled-channels (CC) calculations. To apply the effect of saturation property of nuclear matter, we use the M3Y double-folding model which is corrected with a repulsive term. The repulsive parameters are adjusted to provide an optimum fit to the available experimental fusion cross sections. For each of the Mg-26+Cm-248, S-36+U-238, Ca-48+Pb-208 colliding systems, the best fit to the measured fusion cross sections at high energies is achieved using the CC calculations based on the M3Y+Repulsion potential with a constant value for the strength of the repulsive contact term. While focusing on the heavy-ion fusion reactions existing in the mass range Z(1)Z(2) > 1800 reveals that it is necessary to consider an energy-dependent behavior for the repulsive parameters. When these conditions are imposed on entrance channel potential, it is possible to obtain an excellent description of the fusion data for Ti-50+Bi-209, Ca-40+U-238, and Ca-48+U-238 reactions. Our findings indicate that the extracted values of the strength V-rep of the repulsive contact term increase with increasing incident energy E-c.m.. In addition, we conclude that the repulsive part of the density distribution becomes more diffused with an increase in bombarding energy. (C) 2021 Elsevier B.V. All rights reserved.