Measurements of proton capture in the A=100-110 mass region: Constraints on the in 111 (γ,p)/(γ,n) branching point relevant to the γ process

The γ process is an explosive astrophysical scenario, which is thought to be the primary source of the rare proton-rich stable p nuclei. However, current γ-process models remain insufficient in describing the observed p-nuclei abundances, with disagreements up to two orders of magnitude. A sensitivity study has identified 111In as a model-sensitive (γ,p)/(γ,n) branching point within the γ process. Constraining the involved reaction rates may have a significant impact on the predicted p-nuclei abundances. Here we report on measurements of the cross sections for Pd102(p,γ)Ag103,Cd108(p,γ)In109, and Cd110(p,γ)In111 reactions for proton laboratory energies 3-8 MeV using the high efficiency total absorption spectrometer and the γ-summing technique. These measurements were used to constrain Hauser-Feshbach parameters used in talys 1.9, which constrains the In111(γ,p)Cd110 and In111(γ,n)Ag110 reaction rates. The newly constrained reaction rates indicate that the In111(γ,p)/(γ,n) branching point occurs at a temperature of 2.71±0.05GK, well within the temperature range relevant to the γ process. These findings differ significantly from previous studies and may impact the calculated abundances.