n alpha Resonating-Group Calculation with a Quark-Model G-Matrix NN Interaction

TL;DR

This paper calculates n alpha scattering using a quark-model G-matrix NN interaction within the resonating-group method, revealing consistent exchange behaviors and realistic interaction components without artificial parameters.

Contribution

It introduces a novel application of the energy-independent G-matrix in the RGM framework for n alpha scattering, incorporating nonlocality and momentum dependence explicitly.

Findings

Central and spin-orbit components have reasonable strengths

Exchange terms behave similarly to local effective forces

No artificial parameters needed besides Fermi momentum

Abstract

We calculate n alpha phase-shifts and scattering observables in the resonating-group method, using the nuclear-matter G-matrix of an SU_6 quark-model NN interaction. The G-matrix is generated in the recent energy-independent procedure of the quark-model NN interaction with the continuous prescription for intermediate spectra, by assuming an appropriate Fermi momentum k_F=1.2 fm^-1. The n alpha RGM interaction kernels are evaluated with explicit treatments of the nonlocality and momentum dependence of partial-wave G-matrix components. The momentum dependence of the G-matrix components is different for each of the nucleon-exchange and interaction types. Without introducing any artificial parameters except for k_F, the central and spin-orbit components of the n alpha Born kernel are found to have reasonable strengths under the assumption of a rigid translationally invariant shell-model wave function of the alpha-cluster. The characteristic behaviors of three different exchange terms, corresponding to knockout, heavy-particle pickup and nucleon-rearrangement processes, are essentially the same between the case of previous local effective NN forces and the case of nonlocal G-matrix NN interactions.