Exchange effects in nucleus-nucleus reactions

TL;DR

This paper develops a three-body scattering model for nucleus-nucleus reactions that incorporates core exchange effects, leading to non-local potentials, and successfully reproduces experimental scattering data without parameter fitting.

Contribution

It extends the CDCC formalism by explicitly including core exchange effects and non-local potentials in the scattering calculations.

Findings

Successfully reproduces experimental scattering cross sections.

Identifies backward-angle enhancement due to non-local potentials.

Provides effective local potentials for practical use.

Abstract

We present a scattering model for nuclei with similar masses. In this three-body model, the projectile has a core+valence structure, whereas the target is identical to the core nucleus. The three-body wave functions must be symmetrized for the exchange of the cores. This property gives rise to non-local potentials, which are computed without approximation. The present model is an extension of the Continuum Discretized Coupled Channel (CDCC) formalism, with an additional treatment of core exchange. We solve the coupled-channel system, including non-local terms, by the $R$-matrix method using Lagrange functions. This model is applied to the $^{13}{\rm C}+^{12}$C, $^{13}{\rm N}+^{12}$C and $^{16}{\rm O}+^{12}$C systems. Experimental scattering cross sections are fairly well reproduced without any parameter fitting. The backward-angle enhancement of the elastic cross sections is due to the non-local potential. We discuss in more detail the various non-local contributions and present effective local potentials.