Analysis of the Fusion Hindrance in Mass-symmetric Heavy Ion Reactions

TL;DR

This paper investigates fusion hindrance in mass-symmetric heavy ion reactions using a liquid drop model, identifying the conditions under which fusion is hindered based on nuclear charge and barrier overlap.

Contribution

It introduces a criterion based on barrier positions to determine fusion hindrance in mass-symmetric systems, extending understanding of when hindrance occurs.

Findings

Fusion hindrance is absent for systems with Z ≤ 43.

All mass-symmetric reactions with Z > 43 are fusion-hindered.

The model predicts barrier overlap as a key factor in hindrance occurrence.

Abstract

The fusion hindrance, which is also denominated by the term extra-push, is studied on mass-symmetric systems by the use of the liquid drop model with the two-center parameterization. Following the idea that the fusion hindrance exists only if the liquid drop barrier (saddle point) is located at the inner side of the contact point after overcoming the outer Coulomb barrier, the reactions in which two barriers are overlapped with each other are determined. It is shown that there are many systems where the fusion hindrance does not exist for the atomic number of projectile or target nucleus $Z\leq43$, while for $Z>43$, all of the mass-symmetric reactions are fusion-hindered.