Do right-handed neutrinos exist?

The weak interaction of the four components of the muon is discussed. Using a high-energy pion beam as a source of polarized muons, the components μ^?_R or μ⁺_L can be selected and used in a sensative search for massive right-handed neutrinos. This search may be extended to higher mass by the use of colliding beams of protons and polarized electrons.