Neutrino Physics and the Mirror World

Abstract

Improper Lorentz Transformations can be retained as exact symmetries of Nature if the particle content and gauge group of the Standard Model are doubled. The resulting ``Exact Parity Model (EPM)'' sees each ordinary particle paired with a mirror analogue. If neutrinos have mass and if they mix, then the EPM predicts that each ordinary neutrino will be maximally mixed with its mirror neutrino partner. This provides a very simple explanation for the very large mixing angle observed for atmospheric muon neutrinos by SuperKamiokande and other experiments. Maximal mixing for electron neutrinos is also well motivated by the solar neutrino problem. If small interfamily mixing is switched on, then the LSND anomaly can also be accomodated by the EPM. The EPM thus provides a unified, simple and to some extent predictive framework for explaining all of the anomalous neutrino data. This talk will briefly review the EPM or mirror neutrino scenario.