Photo-disintegration of N=Z light nuclei using SRC-based approach

The outcome of any possible nucleosynthesis scenario is strongly affected by the photodisintegration of nuclei through (γ, N) and (γ, np) channels for Eγ > 10 MeV to a few hundred MeV. Though there is a wide range of phenomenological models for the estimation of excitation functions in this energy region, the exact photodisintegration mechanism is not well understood. The shell-model based approaches have not been successful even for the light nuclei of astrophysical importance like Li. A simple SRC-based approach is employed to calculate the photo-disintegration of light nuclei in the quasideuteron region. Combining the Gunn-Irving photo-disintegration for α-cluster, the proposed approach is used to calculate the total photodisintegration cross-sections for Eγ between 10 to 140 MeV for many of the N=Z light nuclei from He to Ca. Contrary to general perception, the quasideuteron photo-disintegration contribution starts in the GDR region itself and dominates for Eγ > 50 MeV. Along with many interesting new insights, the derivation of the Levinger formula is obtained without any additional assumption. A significant fraction of the photo-disintegration cross-section in GDR region may be accounted by contribution of quasi-α degree of freedom which decreases for higher Eγ. The present work suggests an alternative and viable description of photodisintegration for N=Z nuclei.