Muon capture

Feynman diagram of the muon capture. A negatively charged muon is captured by a proton. The proton is transformed into a neutron and a muon-neutrino is emitted. The interaction is mediated by a W-boson.

Muon capture is the capture of a negative muon by a proton, usually resulting in production of a neutron and a neutrino, and sometimes a gamma photon.

Muon capture by heavy nuclei often leads to emission of particles; most often neutrons, but charged particles can be emitted as well.

Ordinary muon capture (OMC) involves capture of a negative muon from the atomic orbital without emission of a gamma photon:


μ−
 + 
p+
 → 
ν
μ + 
n0

Radiative muon capture (RMC) is a radiative version of OMC, where a gamma photon is emitted:


μ−
 + 
p+
 → 
ν
μ + 
n0
 + 
γ

Theoretical motivation for the study of muon capture on the proton is its connection to the proton's induced pseudoscalar form factor gp.

Practical application - Nuclear waste disposal

Muon capture is being investigated for practical application in radioactive waste disposal, for example in the artificial transmutation of large quantities of long-lived radioactive waste that have been produced globally by fission reactors. Radioactive waste can be transmuted to stable isotopes following irradiation by an incident muon (
μ−
) beam from a compact proton accelerator source.

References