Unraveling the reaction mechanisms leading to partial fusion of weakly bound nuclei

TL;DR

This paper investigates the mechanisms behind partial fusion in collisions involving weakly bound nuclei, revealing that direct capture from the ground state dominates over the two-step dissociation and capture process.

Contribution

It introduces the first implementation of a three-body model of inclusive breakup that accounts for both direct and two-step fusion mechanisms.

Findings

Partial fusion is mainly due to direct capture from the ground state.

The two-step dissociation and capture process plays a lesser role.

The model provides new insights into fusion mechanisms involving weakly bound nuclei.

Abstract

Collisions between complex nuclei may give rise to their total or partial fusion. The latter case is found experimentally to gain importance when one of the colliding nuclei is weakly bound. It has been commonly assumed that the partial fusion mechanism is a two-step process, whose first step is the dissociation of the weakly bound nucleus, followed by the capture of one of the fragments. To assess this interpretation, we present the first implementation of the three-body model of inclusive breakup proposed in the 1980s by Austern et al. [Phys. Rep. 154, 125 (1987)] that accounts for both the direct, one-step, partial fusion and the two-step mechanism proceeding via the projectile continuum states. Contrary to the widely assumed picture, we find that, at least for the investigated cases, the partial fusion is largely dominated by the direct capture from the projectile ground-state.