Evolution of fusion hindrance for asymmetric systems at deep sub barrier energies

TL;DR

This study investigates fusion hindrance phenomena in asymmetric nuclear systems at deep sub-barrier energies, revealing how the effect varies with projectile mass and proposing a transition model from sudden to adiabatic regimes.

Contribution

It provides experimental measurements of fusion cross-sections for 7Li and 12C with 198Pt at low energies and introduces a model explaining the emergence of fusion hindrance.

Findings

Fusion hindrance observed in 12C + 198Pt but not in 7Li + 198Pt.

Hindrance increases with projectile mass from lighter to heavier nuclei.

Weak damping effect of coupling to collective motion in these systems.

Abstract

Measurements of fusion cross-sections of 7Li and 12C with 198Pt at deep sub-barrier energies are reported to unravel the role of the entrance channel in the occurrence of fusion hindrance. The onset of fusion hindrance has been clearly observed in 12C + 198Pt system but not in 7Li + 198Pt system, within the measured energy range. Emergence of the hindrance, moving from lighter (6,7Li) to heavier (12C,16O) projectiles is explained employing a model that considers a gradual transition from a sudden to adiabatic regime at low energies. The model calculation reveals a weak effect of the damping of coupling to collective motion for the present systems as compared to that obtained for systems with heavier projectiles.