Matter enhanced oscillations of accelerator neutrinos

New ranges of neutrino oscillation parameters can be probed by sending accelerator produced neutrinos to large neutrino detectors thousands of kilometers away. Since the neutrino propagation is through the earth, νμ-νe and anti νμ-anti νe oscillations can be quite different from vacuum oscillations. For the accelerator and detector parameters of one such experiment previously suggested, the presence of background matter enhances neutrino mixing for mass differences in the range 0.5 x 10-2 eV2 < m22-m12<5x10-2 eV2 and suppresses mixing below this range. The enhanced range is below that probed by present accelerator or reactor experiments and is of current interest for checking whether the anomalous results observed for atmospheric neutrinos are due to neutrino oscillations. (orig.)