# The puzzle of complete fusion suppression in weakly-bound nuclei: a Trojan Horse effect?

## TL;DR

This paper introduces a new approach to understanding the suppression of complete fusion in reactions involving weakly-bound nuclei, attributing it mainly to non-elastic breakup modes and explaining large alpha yields via a Trojan Horse mechanism.

## Contribution

The paper presents a novel method linking fusion suppression to reaction mechanisms and demonstrates its application to Li+Bi reactions, highlighting the role of non-elastic breakup and Trojan Horse effects.

## Key findings

- Suppression of complete fusion is mainly due to non-elastic breakup modes.
- Elastic breakup plays a minor role in fusion suppression.
- Large alpha yields are explained by a Trojan Horse mechanism.

## Abstract

Experimental studies of nuclear collisions involving light weakly-bound nuclei show a systematic suppression of the complete fusion cross section by $\sim$30\% with respect to the expectation for tightly bound nuclei, at energies above the Coulomb barrier. Although it is widely accepted that the phenomenon is related to the weak binding of these nuclei, the origin of this suppression is not fully understood. In here, we present a novel approach that provides the complete fusion for weakly bound nuclei and relates its suppression to the competition between the different mechanisms contributing to the reaction cross section. The method is applied to the $^{6,7}$Li+$^{209}$Bi reactions, where we find that the suppression of complete fusion is mostly caused by the flux associated with non-elastic breakup modes, such as the partial capture of the projectile (incomplete fusion), whereas the elastic breakup mode is found to play a minor role. Finally, we demonstrate that the large $\alpha$ yields observed in these reactions can be naturally explained as a consequence of a {\it Trojan Horse} mechanism.