Exit-Channel Suppression in Statistical Reaction Theory

TL;DR

This paper investigates how exit channel suppression affects statistical reaction models, using random matrix theory to reveal significant deviations in branching ratios, exemplified by neutron-induced reactions on uranium-235.

Contribution

It introduces a novel application of Gaussian orthogonal ensemble to quantify exit channel suppression in reaction theories, highlighting its impact on branching ratio predictions.

Findings

Exit channel suppression can be substantial in reaction models.

The suppression effect provides insights into the number of exit channels.

Demonstrated with neutron-induced reactions on uranium-235.

Abstract

Statistical reaction theories such as Hauser-Feshbach assume that branching ratios follow Bohr's compound nucleus hypothesis by factorizing into independent probabilities for different channels. Corrections to the factorization hypothesis are known in both nuclear theory and quantum transport theory, particularly an enhanced memory of the entrance channel. We apply the Gaussian orthogonal ensemble to study a complementary suppression of exit channel branching ratios. The effect can be large enough to provide information on the number of exit channels. The effect is demonstrated for the branching ratios of neutron-induced reactions on a $^{235}$U target.