Refractive scattering and the nuclear rainbow in the interaction of12, 13C with12C at 20MeV/N

Abstract

The elastic and inelastic scattering and the neutron transfer have been measured for the systems 1ac+12C and 1ac+12C at 20MeV/N up to 0cm=60 ~ with the Q3D-spectrometer. The angular distributions of the elastic scattering show an enhanced cross section at angles larger than 40 ~ . It can be identified as refractive scattering with the clear signature of a nuclear rainbow. L-cut-off calculations show that these contributions come from L-values which are significantly lower than the grazing L-value. The deflection function has a broad minimum in this L-range which is typical for rainbow scattering. The S-matrix is decomposed by a phenomenological parametrization into a refractive and a diffractive part. The interference of these amplitudes plays an important role in the rainbow enhancement. The spatial localization of the refractive scattering is deduced from the turning points of the corresponding trajectories; a localization between 2.5 fm and 4 fm is found. Semi-classical calculations with complex trajectories in the single-turning-point approximation show good agreement with the quantummechanical calculations. Refractive contributions are not observed in the inelastic scattering. This can be explained by reducing the strength of the conventional collective form factor in the internal region. In contrast to this the enhancement at large angles is seen in the one-neutron transfer channels where the refractive scattering is dominant. This is the first observation of such contributions to heavy-ion transfer reactions.

Unification of Airy structure in inelasticα+16O scattering andα-cluster structure with core excitation in20Hirabayashi1, Ohkubo2 2013Phys. Rev. C211240View full textAdd to dashboardCite

“…However, similar to the rainbow in elastic scattering, the study of the inelastic rainbow scattering will be very useful in understanding the interaction potential for the inelastic channels [5,[10][11][12][13]. The mechanism of the nuclear rainbow and the Airy structure in inelastic scattering has been studied for the α + 40 Ca and 6 Li + 12 C systems by using a phenomenological form factor [14,15].…”

Refractive scattering and reactions, comparison of two systems:16O+16O and20Ne+12C

“…A large number of theoretical and experimental studies have been devoted in the past decade to the study of the nucleus-nucleus optical potential at small distances, which would be manifested through a refractive part of the elastic angular distributions [1][2][3][4]. Refractive or rainbow scattering has been well established in the scattering of e-particles [5] and recently in reactions induced by 3He [6] by the observation of the nuclear rainbow pattern at large scattering angles.…”

Nonlocal Description of the Nucleus-Nucleus Interaction

“…In the nucleus-nucleus case, significant progress has been achieved concerning this question during the last decade [1], as a consequence of the measurement of accurate and extensive elastic scattering data at intermediate energies. Nuclear rainbow scattering, first observed in a systems [2][3][4] and later in light heavy ions [5][6][7], probes the nucleus-nucleus potential not only at the surface region but also at smaller distances, and ambiguities in the real part of the potentials have been removed. The resulting phenomenological interactions have significant dependence upon the bombarding energies.…”