January 1, 1999 Book section Open Access

Atmoshperic Neutrino Oscillation Results with MACRO at Gran Sasso Laboraratory

M. Spinelli

We present updated results of the measurement of the atmospheric neutrino flux with the MACRO detector at Gran Sasso, using three data sets spread in a large energy range. In the high energy range, the upgoing throughgoing muon data set is in favor of νμ →ντ oscillation hypothesis with a probability of 36.6% against the 0.36% for the no oscillation hypothesis.In the low energy range, the two data set are also in favor to the oscillation hypothesis showing a large defict for IU events and a reduced defict for US+ID events, since only the US events ( |50% ) are expected to oscillate Assuming a νμ →ντ oscillation scheme, the results suggest a large range of the parameter values centered around Dm2=0.0025 eV2, sin2 2q = 1.