Extracting matter effects, masses and mixings at a neutrino factory

We discuss and quantify different possibilities to determine matter effects , the value and the sign of Delta m(31)(2), as well as the magnitude of sin (2)2 theta(13) in very long baseline neutrino oscillation experitnenls. We study neutrino oscillation at a neutrino factory in the nu(mu) --> nu(mu) d isappearance and nu(e) --> nu(mu) appearance channels with and without muon charge identification. One possibility is to analyze the nu(e) --> nu(mu) appearance channels leading to wrong sign muon events, which requires howev er very good muon charge identification. Without charge identification it i s still possible to operate the neutrino factory both with mu(-) and mu(+) beams and to analyze the differences in the total neutrino event rate spect ra. We show that this leads already to a quite good sensitivity, which may be important if right sign charge rejection capabilities are insufficient. With muon charge identification one can study the nu(mu) --> nu(mu) disappe arance and the nu(e) --> nu(mu) appearance channels independently. The best method is finally achieved by combining all available information of the n u(mu) --> nu(mu) disappearance and nu(e) --> nu(mu) appearance channels wit h charge identification and we show the sensitivity which can be achieved. (C) 2000 Elsevier Science B.V. All rights reserved.