Neutrino factory - ionization cooling, emittance exchange, and ν superbeam at BNL?

Muon collider, neutrino factory and/or a neutrino superbeam are interesting and needed to provide a probe for fundamental particle physics. In our collabortion studies we have realized some important issues needed before building a collider (cost, cooling demonstration, radiation, etc). Muon cooling is a key factor in design of muon collider, (to a less degree) muon storage ring, and neutrino factory. We present a brief overview on cooling and beam emittance dynamics, and discuss future neutrino superbeam possiblities at BNL (to be further explored at Snowmass2001)