The Statistical Properties of ⁹²Mo and Implications for the p-process

A challenging part of the question of how elements heavier than iron are created in extreme, astro-physical environments is the creation of p-isotopes. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions for the production of these isotopes. The p-isotope ⁹²Mo represents one of the most severe cases of underproduction. The main destruction mechanism of this isotope in the standard description of the p-process is through the ⁹²Mo(γ, p)⁹¹Nb reaction. Measurements on the nuclear level density and γ strength function of ⁹²Mo have been carried out at the Oslo Cyclotron Laboratory. TALYS cross section and reaction rate calculations using the experimental results as input are presented, providing constraints on the ⁹¹Nb(p, γ)⁹²Mo (and consequently the inverse) reaction rate. Further, the reaction rates extracted in this work were used in network calculations for the scenario of a p-process taking place in a type II supernova explosion as the shock front passes through the O-Ne layer of a 25 solar mass star. We conclude that there is no salvation in the nuclear input alone in the ⁹²Mo underproduction problem, strengthening previous conclusions pointing towards more exotic astrophysical scenarios.