Muon capture (original) (raw)

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Capture of a negative muon by a proton

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.

Except for the flavor of neutrino, it has exactly the same result as electron capture, except that the great mass-energy of the muon makes it allowed for all nuclei and there is so much excess energy that a nucleus can disintegrate; for heavy nuclei this leads to emission of nuclear 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+
→ νμ + n0

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

μ−
+ p+
→ νμ + 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.

Nuclear waste disposal

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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.