Observation of Airy minimum in elastic and inelastic scattering of $^3$He from $^{12}$C at 50.5 and 60 MeV and alpha particle condensation in $^{12}$C

TL;DR

This study observes the Airy minimum in elastic and inelastic scattering of helium-3 from carbon-12 at specific energies, providing evidence for alpha particle condensation in the Hoyle state through detailed scattering analysis.

Contribution

The paper presents the first clear observation of the Airy minimum in helium-3 scattering from carbon-12 and supports the alpha condensate nature of the Hoyle state via coupled channels analysis.

Findings

Airy minimum observed in scattering data

Evidence supporting alpha particle condensate in Hoyle state

Analysis confirms large radius of dilute matter in Hoyle state

Abstract

Angular distributions for elastic and inelastic scattering of $^3$He from $^{12}$C were measured at energies 50.5 and 60 MeV. The Airy minimum of the prerainbow scattering was clearly observed in the angular distributions for the 0$_2^+$ (7.65 MeV) state of $^{12}$C (Hoyle state). The experimental results were analyzed with a coupled channels method with double folding potentials derived from the microscopic wave functions for the ground 0$_1^+$, 2$^+$ (4.44 MeV), 3$^-$ (9.64 MeV) and 0$_2^+$ states. The analysis supports the view that the Hoyle state is a three alpha particle condensate with a large radius of dilute matter distribution.