Atmospheric neutrino oscillations with the MACRO detector

Abstract

After a short overview of the MACRO detector, located at the Gran Sasso Laboratory, I shall present and discuss the results on atmospheric muon neutrino oscillations, concerning low (<E_nu> ~ 4 GeV) and high (<E_nu> ~ 50 GeV) energy data. Using the Multiple Coulomb Scattering of muons inside the lower part of the detector, estimates of the neutrino energy were made event by event for the high energy sample. The data on angular distributions, absolute flux and L/E_nu distribution favor nu_mu <--> nu_tau oscillations with maximal mixing and Delta m^2=2.5 x 10^-3 eV^2.