The $^{22}$Ne($\alpha$,n)$^{25}$Mg neutron source: latest experimental results and prospects

TL;DR

This paper reviews recent experimental findings on the $^{22}$Ne($ extalpha$,n)$^{25}$Mg reaction rate, highlighting the non-contribution of a key state and discussing potential contributions from neighboring states at stellar temperatures.

Contribution

It provides an updated assessment of the reaction rate, clarifies the role of specific nuclear states, and discusses experimental uncertainties affecting stellar neutron source modeling.

Findings

The $^{26}$Mg state at 11.15 MeV has non-natural parity and does not contribute to the reaction rate.

Other neighboring states may influence neutron yields at stellar temperatures.

Experimental data helps resolve previous controversies about reaction contributions.

Abstract

The current status of the reaction rate of $^{22}$Ne($\alpha$,n)$^{25}$Mg is summarized. Among the latest new results, probably the most relevant is the conclusion that the E$_x$=11.15 MeV state in $^{26}$Mg has a non-natural parity, so it does not contribute to the rates of the $\alpha$ + $^{22}$Ne reactions. However, it may be possible that other neighboring states contribute to the neutron yield at stellar temperatures. Here we make an account of some of the experimental work in the literature that is relevant to this state. Indeed, it would have been possible to avoid the controversy regarding this state before it even started.