Muon capture

A Feynman diagram of the muon capture.

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

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

References

• T. Gorringe and H.W. Fearing (2004). "Induced pseudoscalar coupling of the proton weak interaction". Rev.Mod.Phys. 76: 31–91. arXiv:nucl-th/0206039. Bibcode:2003RvMP...76...31G. doi:10.1103/RevModPhys.76.31. 
• V.A. Andreev; et al. (2007). "Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling g_P". arXiv:0704.2072.