Prerainbow Oscillations in $^3$He Scattering from the Hoyle State of $^{12}$c and Alpha Particle Condensation

TL;DR

This paper investigates $^3$He scattering from the Hoyle state of $^{12}$C, revealing prerainbow oscillations that support the hypothesis of alpha particle condensation due to the state’s dilute density.

Contribution

It demonstrates that the prerainbow oscillations in $^3$He scattering are sensitive to the density distribution of the Hoyle state, providing evidence for alpha particle condensation.

Findings

The Airy minimum for the Hoyle state shifts to larger angles.

The scattering data supports the dilute density of the Hoyle state.

Results align with alpha particle condensation models.

Abstract

$^3$He+$^{12}$C scattering is studied in a coupled channel method by using a double folding model with microscopic wave functions of $^{12}$C. Experimental angular distributions in elastic and inelastic scattering to the $2^+$ (4.44 MeV), 0$^+_2$ (7.65 MeV) and 3$^-$ (9.63 MeV) states of $^{12}$C are well reproduced. It is found that the Airy minimum of the prerainbow oscillations for the Hoyle state is considerably shifted to a larger angle due to its dilute density distribution compared with that of the normal ground state in agreement with the idea of $\alpha$ particle condensation.