UC Berkeley

One of the greatest questions for modern physics to address is how elements heavier than iron are created in extreme astrophysical environments. A particularly challenging part of that question is the creation of the so-called p-nuclei, which are believed to be mainly produced in some types of supernovae. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions. In this work, we present for the first time measurements on the nuclear level density and average γ strength function of Mo92. State-of-the-art p-process calculations systematically underestimate the observed solar abundance of this isotope. Our data provide stringent constraints on the Nb91(p,γ)Mo92 reaction rate, which is the last unmeasured reaction in the nucleosynthesis puzzle of Mo92. Based on our results, we conclude that the Mo92 abundance anomaly is not due to the nuclear physics input to astrophysical model calculations.