The final analysis of atmospheric neutrino events collected with the MACRO detector is presented. Three different classes of events, generated by neutrinos in different energy ranges, are studied looking at rates, angular distributions and estimated energies. The results are consistent for all the subsamples and indicate a flux deficit that depends on energy and path length of neutrinos. The no -oscillation hypothesis is excluded at about 5 standard deviations, while the hypothesis of muon neutrino oscillating in tau neutrino gives a satisfactory description of all data. The parameters with highest probability in a two flavour scenario are maximum mixing and Delta m^2 = 0.0023 eV^2. This result is independent of the absolute normalization of the atmospheric neutrino fluxes. The data can also be used to put experimental constrain on this normalization.
Measurements of atmospheric muon neutrino oscillations, global analysis of the data collected with MACRO detector
DE MITRI, IVAN
2004-01-01
Abstract
The final analysis of atmospheric neutrino events collected with the MACRO detector is presented. Three different classes of events, generated by neutrinos in different energy ranges, are studied looking at rates, angular distributions and estimated energies. The results are consistent for all the subsamples and indicate a flux deficit that depends on energy and path length of neutrinos. The no -oscillation hypothesis is excluded at about 5 standard deviations, while the hypothesis of muon neutrino oscillating in tau neutrino gives a satisfactory description of all data. The parameters with highest probability in a two flavour scenario are maximum mixing and Delta m^2 = 0.0023 eV^2. This result is independent of the absolute normalization of the atmospheric neutrino fluxes. The data can also be used to put experimental constrain on this normalization.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
