Branchings in the gamma process path revisited

Abstract

The location of the (gamma,p)/(gamma,n) and (gamma,alpha)/(gamma,n) line at gamma process temperatures is discussed, using updated reaction rates based on global Hauser-Feshbach calculations. The results can be directly compared with classic gamma process discussions. The nuclei exhibiting the largest sensitivity to uncertainties in nuclear structure and reaction parameters are specified, and suggestions for experiments are made. Additionally, the effect of employing two recent global alpha+nucleus potentials is discussed. It is found that branchings at higher mass depend more sensitively on these potentials. The case of Sm-146/Sm-144 production is addressed separately. Also, in this case the more recent alpha+nucleus potentials seem to address the issues concerning the production of these Sm isotopes in massive stars. In conclusion, it is found that it is unlikely that the calculated underproduction of p nuclides in the Mo-Ru region is due to nuclear physics deficiencies but that problems at higher mass number may still be solved by improved nuclear input.