Completing the nuclear reaction puzzle of the nucleosynthesis of 92Mo

TL;DR

This paper provides new nuclear data for $^{92}$Mo, constraining reaction rates and suggesting that the abundance anomaly of this isotope is not due to nuclear physics uncertainties, aiding understanding of p-nuclei synthesis.

Contribution

First measurements of nuclear level density and strength function of $^{92}$Mo, refining reaction rate estimates for nucleosynthesis models.

Findings

Data constrains $^{91}$Nb$(p,{ extgamma})^{92}$Mo reaction rate

Nuclear physics input unlikely to explain $^{92}$Mo abundance anomaly

Improves understanding of p-process nucleosynthesis

Abstract

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 strength function of $^{92}$Mo. State-of-the-art p-process calculations systematically underestimate the observed solar abundance of this isotope. Our data provide stringent constraints on the $^{91}$Nb$(p,{\gamma})^{92}$Mo reaction rate, which is the last unmeasured reaction in the nucleosynthesis puzzle of $^{92}$Mo. Based on our results, we conclude that the $^{92}$Mo abundance anomaly is not due to the nuclear physics input to astrophysical model calculations.