Level structure of 31S: From low excitation energies to the region of interest for hydrogen burning in novae through the 30P(p,γ)31S reaction

Comprehensive measurements of the excitation energy and spin-parity assignments for states in S-31 are presented, from the first excited state, up to energies relevant for the P-30(p,gamma)S-31 reaction in ONe novae. This reaction rate strongly influences heavy element abundances in novae ejecta. States in S-31 are paired with their P-31 analogues using gamma rays detected with the Gammasphere detector array following the Si-28(He-4, n) fusion-evaporation reaction. The evolution of mirror energy differences is explored and the results are compared with new shell-model calculations. The excellent agreement observed in this work between experimental data and shell-model calculations provides confidence in using computed estimates in situations where experimental data are unavailable.