Updated global analysis of the atmospheric neutrino data in terms of neutrino oscillations

A global analysis of all the available atmospheric neutrino data is presented in terms of neutrino oscillations in the ν_μ→ν_τ and ν_μ→ν_s channels, where ν_s denotes a sterile neutrino. We perform our analysis of the contained events data as well as the upward-going neutrino-induced muon fluxes. In addition to the previous data samples of Fréjus, Nusex, IMB and Kamioka experiments, we include the full data set of the 52 kton-yr of Super-Kamiokande, the recent 4.6 kton-yr contained events of Soudan2 and the results on upgoing muons from the MACRO and Baksan detectors. From the statistical analysis it emerges that the ν_μ→ν_τ channel provides the best agreement with the combined data, with a best fit point of sin²(2θ)=0.99 and Δm²=3.0×10^-3 eV². Although somehow disfavoured, the ν_μ→ν_s channels cannot be ruled out on the basis of the global fit to the full set of observables.