Mass measurements of proton-rich nuclides in the vicinity of ⁹²Ru and ⁹³Rh for νp-process models

One of the long-standing questions in our understanding of the origin of the elements is the significant underproduction of light-p nuclei such as ⁹²Mo and ⁹⁴Mo by models of nucleosynthesis in various astrophysical scenarios. The recently proposed νp-process [1], which occurs due to the interaction of the neutrino wind with the proton-rich ejecta of core collapse supernova explosions, is a process which could resolve the underproduction of ⁹²Mo and ⁹⁴Mo. The final abundances of these two isotopes as well as any others synthesized by the νp-process depend directly on the values of the proton separation energies, S_p, along the νp-process reaction path; the S_p value of ⁹³Rh is thought to be especially critical to the relative production of ⁹²Mo and ⁹⁴Mo [2]. Due to the absence of mass measurements in this region S_p(⁹³Rh) and many of the other required S_p values were not well known. Recent mass measurements performed with the Canadian Penning Trap mass spectrometer have reduced uncertainties in the S_p values of many of the proton-rich nuclei between Mo and Pd including S _p(⁹³Rh) by factors of as much as 60. These measurements and the resulting implications for both the ∪-process path and the ⁹²Mo/⁹⁴Mo abundance ratio will be discussed.