Ne20(p, p′γ)Angular Correlations at Low Energy

${\mathrm{Ne}}^{20}(p, p^{\prime }\gamma )$ 1.63-MeV angular correlations have been measured in the 5.2-6.10 MeV energy range, where the elastic and inelastic excitation functions vary in a compensating manner. The measurements have been made at 5.25-, 5.55-, and 6.10-MeV proton energies, the position of the proton detector being at 60°, 90°, and 120°. One obtains strong angular correlation functions of the form $A+B{sin}^{2}2(\theta -{\theta }_0)$, where ${\theta }_0$ defines the axis of symmetry. The angular correlation curves are insensitive to a change of the incident proton energy and ${\theta }_0$ is situated in the proximity of the recoil direction ${\theta }_R$ of the nucleus. These facts could constitute an argument in favor of the direct-interaction mechanism.