Extracting matter effects, masses and mixings at a neutrino factory

Abstract

We discuss and quantify different possibilities to determine matter effects,\nthe value and the sign of $Delta m^2_{31}$, as well as the magnitude of $\\sin^2\n2\\theta_{13}$ in very long baseline neutrino oscillation experiments. We study\nneutrino oscillation at a neutrino factory in the $\\nu_\\mu\\to\\nu_\\mu$\ndisappearance and $\\nu_e\\to\\nu_\\mu$ appearance channels with and without muon\ncharge identification. One possibility is to analyze the $\\nu_e\\to\\nu_\\mu$\nappearance channels leading to wrong sign muon events, which requires however\nvery good muon charge identification. Without charge identification it is still\npossible to operate the neutrino factory both with $\\mu^-$ and $\\mu^+$ beams\nand to analyze the differences in the total neutrino event rate spectra. We\nshow that this leads already to a quite good sensitivity, which may be\nimportant if right sign charge rejection capabilities are insufficient. With\nmuon charge identification one can study the $\\nu_\\mu\\to\\nu_\\mu$ disappearance\nand the $\\nu_e\\to\\nu_\\mu$ appearance channels independently. The best method is\nfinally achieved by combining all available information of the\n$\\nu_\\mu\\to\\nu_\\mu$ disappearance and $\\nu_e\\to\\nu_\\mu$ appearance channels\nwith charge identification and we show the sensitivity which can be achieved.\n