PHYSICS OPPORTUNITIES AT NEUTRINO FACTORIES*

This article describes the physics capabilities of a future facility that would provide extremely intense and clean neutrino beams. This facility, called a neutrino factory, consists of a muon storage ring with long straight sections, pointed at experimental areas both near and far. Given the expected intensity of muons stored in the rings, this facility could give the lepton sector what decades of precision kaon and B experiments have given the quark sector. One would measure with unprecedented precision the parameters of the leptonic mixing matrix, explore the neutrino mass pattern, and ultimately search for CP violation in the leptonic sector. In addition, the high fluxes at a neutrino factory would open up a whole new field in precision neutrino scattering physics close to the ring itself.