Study of Cluster Structures in Nuclei through the Ratio Method. A Tribute to Mahir Hussein

TL;DR

This paper reviews the Ratio Method, a novel reaction observable that enhances sensitivity to nuclear structure by comparing angular distributions in elastic scattering and breakup, applicable to halo nuclei at various energies.

Contribution

It introduces and extends the Ratio Method for studying loosely-bound nuclear systems, reducing reaction mechanism dependence and increasing structural sensitivity.

Findings

The Ratio Method effectively isolates nuclear structure information.

It is applicable to low-energy and proton-halo nuclei.

The method minimizes uncertainties from optical potential choices.

Abstract

For one-neutron halo nuclei, the cross section for elastic scattering and breakup at intermediate energy exhibit similar angular dependences. The Recoil Excitation and Breakup (REB) model of reactions elegantly explains this feature. It also leads to the idea of a new reaction observable to study the structure of loosely-bound nuclear systems: the Ratio. This observable consists of the ratio of angular distributions for different reaction channels, viz. elastic scattering and breakup, which cancels most of the dependence on the reaction mechanism; in particular it is insensitive to the choice of optical potentials that simulate the projectile-target interaction. This new observable is very sensitive to the structure of the projectile. In this article, we review the Ratio Method and its extension to low beam energies and proton-halo nuclei.