Comment on "Nuclear Excitation by Free Muon Capture"

TL;DR

This paper critically evaluates a proposed nuclear excitation process via free muon capture, arguing that it is unlikely to be detectable or practically significant due to competing mechanisms and nuclear decay pathways.

Contribution

The paper provides a critical analysis of a proposed nuclear excitation method, highlighting its limitations and the reasons it is unlikely to be experimentally observable.

Findings

The process excites high energy nuclear levels unlikely to decay to isomers.

Most incident muons do not meet the energy criteria for the process.

Muonic capture shortens the lifetime of excited nuclei.

Abstract

In the paper [1] the process of free muon capture with simultaneous excitation of a nuclear isomer has been suggested, claiming that ``the effect can be detectable for selected isotopes". Here, we argue that this claim can not be confirmed. Briefly, the process is far from the dominant mechanism for nuclear excitation; it excites high energy nuclear levels that will not generally decay to the isomer; the proposal assumes all incident muons will fulfil energy criteria, ignoring dominant capture paths; and nuclei excited by muons will have a shortened lifetime due to muonic capture.