Unification of Airy structure in inelastic $\alpha$ +$^{16}$O scattering and $\alpha$-cluster structure with core excitation in $^{20}$Ne

TL;DR

This paper unifies the understanding of Airy structures in inelastic and elastic alpha + oxygen scattering with alpha-cluster states in neon-20, demonstrating a common origin and reproducing experimental observations through microscopic calculations.

Contribution

It presents a unified theoretical framework linking Airy structures in scattering with alpha-cluster states in neon-20, incorporating core excitation effects.

Findings

Reproduces the energy evolution of Airy minima in scattering data.

Identifies the connection between prerainbow/rainbow phenomena and alpha-cluster states.

Shows the emergence of the K=0_3^+ alpha-cluster band is related to inelastic scattering features.

Abstract

The Airy structure of the nuclear rainbow and prerainbow in inelastic and elastic $\alpha+^{16}$O scattering is studied with the coupled channel method using a folding potential derived from the microscopic wave functions of $^{16}$O. The theoretical calculations reproduce the characteristic energy evolution of the Airy minimum of the experimental angular distributions. The energy levels with $\alpha$-cluster structure in $^{20}$Ne are reproduced well using the potentials determined from the analysis of scattering. It is shown that the emergence of the $K=0_3^+$ $\alpha$-cluster band with core excitation at 7.19 MeV in $^{20}$Ne is intimately related to the emergence of the prerainbow and rainbow in inelastic scattering to the $^{16}$O($0^+_2$). It is found that the $\alpha$-cluster states with core excitation, the prerainbow and the rainbow in inelastic scattering are understood in a unified way as well as in the case of elastic scattering.