Atmospheric neutrino oscillations with the MACRO detector

TL;DR

This paper reports on atmospheric muon neutrino oscillation results from the MACRO detector, showing evidence for nu_mu <--> nu_tau oscillations with maximal mixing and a specific mass-squared difference, across different energy ranges.

Contribution

It provides new measurements of atmospheric neutrino oscillations using the MACRO detector, including energy estimates event-by-event at high energies, supporting the nu_mu <--> nu_tau oscillation hypothesis.

Findings

Data favor nu_mu <--> nu_tau oscillations with maximal mixing.

Energy estimates for high-energy neutrinos were obtained event-by-event.

Results support a Delta m^2 of approximately 2.5 x 10^-3 eV^2.

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.