Photon-induced Nucleosynthesis: Current Problems and Experimental Approaches

TL;DR

This paper reviews photon-induced reactions crucial for p-nuclei nucleosynthesis, proposing improved methods and experimental approaches using synchrotron radiation to better understand and reduce uncertainties in astrophysical models.

Contribution

It introduces an improved astrophysical S-factor based on Coulomb wave functions and highlights synchrotron radiation at SPring-8 as a promising experimental tool.

Findings

S_C(E) reduces energy dependence in heavy nuclei reactions

Blackbody synchrotron radiation can simulate stellar conditions

Experimental data can refine nuclear parameters in models

Abstract

Photon-induced reactions play a key role in the nucleosynthesis of rare neutron-deficient p-nuclei. The paper focuses on (gamma,alpha), (gamma,p), and (gamma,n) reactions which define the corresponding p-process path. The relation between stellar reaction rates and laboratory cross sections is analyzed for photon-induced reactions and their inverse capture reactions to evaluate various experimental approaches. An improved version S_C(E) of the astrophysical S-factor is suggested which is based on the Coulomb wave functions. S_C(E) avoids the apparent energy dependence which is otherwise obtained for capture reactions on heavy nuclei. It is found that a special type of synchrotron radiation available at SPring-8 that mimics stellar blackbody radiation at billions of Kelvin is a promising tool for future experiments. By using the blackbody synchrotron radiation, sufficient event rates for (gamma,alpha) and (gamma,p) reactions in the p-process path can be expected. These experiments will provide data to improve the nuclear parameters involved in the statistical model and thus reduce the uncertainties of nucleosynthesis calculations.