CP-violation in 3- and 4-family at the Neutrino Factory

The leptonic CP-violating phase delta can be measured with a Neutrino Facto ry with 2 x 10(20) useful muons per year, if the solar neutrino problem is solved by the LMA-MSW solution, with Deltam(12)(2) greater than or equal to 2 x 10(-5) eV(2) (in this analysis a 40 kT magnetized iron detector is con sidered, taking into account its efficiencies and backgrounds). If LSND is confirmed, CP-violating phenomena in four-family scenarios can be most easi ly addressed with a small 1 kT detector at L = O(10) km (no detailed analys is of the detector efficiencies and backgrounds has been performed in this case).