Extracting Matter Effects, Masses and Mixings at a Neutrino Factory

Abstract

We discuss and quantify different possibilities to determine matter effects, the value and the sign of $Delta m^2_{31}$, as well as the magnitude of $\sin^2 2θ_{13}$ in very long baseline neutrino oscillation experiments. We study neutrino oscillation at a neutrino factory in the $ν_μ\toν_μ$ disappearance and $ν_e\toν_μ$ appearance channels with and without muon charge identification. One possibility is to analyze the $ν_e\toν_μ$ appearance channels leading to wrong sign muon events, which requires however very good muon charge identification. Without charge identification it is still possible to operate the neutrino factory both with $μ^-$ and $μ^+$ beams and to analyze the differences in the total neutrino event rate spectra. 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 $ν_μ\toν_μ$ disappearance and the $ν_e\toν_μ$ appearance channels independently. The best method is finally achieved by combining all available information of the $ν_μ\toν_μ$ disappearance and $ν_e\toν_μ$ appearance channels with charge identification and we show the sensitivity which can be achieved.