Analysis of oscillations of atmospheric neutrinos

Abstract

We briefly review the current status of standard oscillations of atmospheric neutrinos in schemes with two, three, and four flavor mixing. It is shown that, although the pure ν_μ-->ν_τchannel provides an excellent 2νfit to the data, one cannot exclude, at present, the occurrence of additional subleading ν_μ-->ν_e oscillations (3νschemes) or of sizable ν_μ-->ν_s oscillations (4νschemes). It is also shown that the wide dynamical range of energy and pathlength probed by the Super-Kamiokande experiment puts severe constraints on nonstandard explanations of the atmospheric neutrino data, with a few notable exceptions.