Introduction to muon cooling

We present an overview of the process of ionization cooling, which is useable for cooling muons. In ionization cooling, particles pass through a material medium and lose energy (momentum) through ionization interactions, and this is followed by beam reacceleration in RF cavities. The cooling can be sufficient to enable use of muons in high-intensity neutrino factories or high-luminosity μ+−μ− colliders. The status of μ-cooling research is discussed.