Investigation of multi-step effects for proton inelastic scattering to the $2^{+}_{1}$ state in $^6$He

TL;DR

This paper investigates multi-step effects in proton inelastic scattering to the 2+ state in helium-6 using the continuum-discretized coupled-channels method, highlighting the importance of multi-step contributions and proposing a model-space independent calculation approach.

Contribution

It introduces a one-step calculation method that avoids model-space dependence for fragmented resonant states in CDCC analysis.

Findings

Multi-step effects significantly influence cross sections.

Proposed method reduces model-space dependence.

Clarifies role of multi-step processes in scattering analysis.

Abstract

Multi-step effects between bound, resonant, and non-resonant states have been investigated by the continuum-discretized coupled-channels method (CDCC). In the CDCC, a resonant state is treated as multiple states fragmented in a resonance energy region, although it is described as a single state in usual coupled-channel calculations. For such the fragmented resonant states, one-step and multi-step contributions to the cross sections should be carefully discussed because the cross sections obtained by the one-step calculation depend on the number of those states, which corresponds to the size of the model space. To clarify the role of the multi-step effects, we propose the one-step calculation without model-space dependence for the fragmented resonant states. Furthermore, we also discuss the multi-step effects between the ground, $2^{+}_{1}$ resonant, and non-resonant states in $^6$He for proton inelastic scattering.