Deformation in 28Si* produced via 16O + 12C reaction

TL;DR

This study investigates the deformation of 28Si* nuclei produced in 16O + 12C reactions by analyzing alpha particle spectra and comparing them with statistical models, revealing larger-than-expected deformations and suggesting possible orbiting phenomena.

Contribution

The paper provides a detailed comparison of experimental alpha spectra with statistical models using different deformation assumptions, highlighting larger deformations than RLDM predictions.

Findings

Deformations larger than RLDM values.

Good explanation with frozen deformation approximation.

Possible contribution of equilibrium orbiting.

Abstract

The energy spectra of the $\alpha$ particles emitted in the reactions $^{16}$O (7-10 MeV/nucleon) + $^{12}$C have been measured in the center of mass angular range of 25$^\circ$ $\lesssim \theta_{c.m.} \lesssim$ 70$^\circ$. The experimental energy spectra have been compared with those obtained from the statistical model calculation with "deformability" parameters predicted by rotating liquid drop model (RLDM) and also fitted the same with optimized "deformability" parameters, which are quite different from the respective RLDM values. The data have also been found to be explained quite well using "frozen" deformation approximation, where the "deformability" parameters have been kept fixed at RLDM values of the parent nucleus throughout the decay process. The effective radius in the latter case is smaller compared to that obtained using the optimized parameters; however, in both cases, the deformations (effective radii) are larger than the corresponding RLDM values. So, considering the uncertainties in the estimation of actual compound nucleus deformations, it can, only qualitatively, be said that equilibrium orbiting, which is similar to particle evaporation in time scale, could also be one of the contributing factors for the observed deformation.