Physical reach of a neutrino factory in the 2+2 and 3+1 four-family scenario

We compare the physical reach of a Neutrino Factory in the 2+2 and 3+1 four-family models, with similar results in the two schemes; in both cases huge CP-violating effects can be observed with a near detector in the νμ→ντ channel. We also study the capability of long baseline experiments (optimized for the study of the three-family mixing parameter space) in distinguishing a three (active) neutrino model from a four-family scenario.