MACRO results on atmospheric neutrino oscillations

TL;DR

The MACRO experiment's final results support muon neutrino to tau neutrino oscillations with maximal mixing and a specific mass-squared difference, based on various event analyses and energy estimations.

Contribution

This paper provides comprehensive final results on atmospheric neutrino oscillations, utilizing multiple event topologies and Coulomb scattering for energy estimation, confirming oscillation parameters.

Findings

Data favor nu_mu --> nu_tau oscillations with maximal mixing

Energy and angular distributions support oscillation hypothesis

Ratios are robust against Monte Carlo normalization uncertainties

Abstract

The final results of the MACRO experiment on atmospheric neutrino oscillations are presented. The data concern different event topologies with average neutrino energies of ~ 3 and ~ 50 GeV. Multiple Coulomb Scattering of the high energy muons was used to estimate the neutrino energy event by event. The angular distributions, the L/E_nu distribution, the particle ratios and the absolute fluxes all favour nu_mu --> nu_tau oscillations with maximal mixing and Delta m^2 ~ 0.0023 eV^2. Emphasis is given to measured ratios which are not affected by Monte Carlo (MC) absolute normalization; a discussion is made on MC uncertainties.