The silver channel at the neutrino factory

We notice that looking for V-e --> Vtau at the same time as V-e --> vu oscillations could significantly help to reduce the errors in the leptonic CP-violating phase 3 measurement. We show how the V-e --> Vmu (golden) and v(e) --> vtau (silver) transitions observed at an OPERA-like 2 kton leademulsion detector at L = 732 km, in combination with the v(e) --> vmu transitions observed at a 40 kton magnetized iron detector with a baseline of L = 3000 km, strongly reduce the so-called (theta(13), delta) ambiguity. We also show how a moderate increase in the OPERA-like detector mass (4 kton instead of 2 kton) completely eliminates the clone regions even for small values Of theta(13). (C) 2002 Elsevier Science B.V. All rights reserved.