Muon energy reconstruction in ANTARES and its application to the diffuse neutrino flux

TL;DR

This paper presents methods for reconstructing muon energy in the ANTARES neutrino telescope, enabling improved sensitivity to diffuse astrophysical neutrino fluxes by effectively distinguishing signal from background.

Contribution

The study introduces three muon energy reconstruction methods and demonstrates their effectiveness in enhancing ANTARES sensitivity to diffuse neutrino fluxes.

Findings

Achieved an energy resolution of a factor of ~2 above 1 TeV.

Set a sensitivity limit of E^2 dF/dE < 8×10^-8 GeV cm^-2 s^-1 sr^-1 after 1 year.

Successfully rejected atmospheric muon background using dedicated variables.

Abstract

The European collaboration ANTARES aims to operate a large neutrino telescope in the Mediterranean Sea, 2400 m deep, 40 km from Toulon (France). Muon neutrinos are detected through the muon produced in charged current interactions in the medium surrounding the detector. The Cherenkov light emitted by the muon is registered by a 3D photomultiplier array. Muon energy can be inferred using 3 different methods based on the knowledge of the features of muon energy losses.They result in an energy resolution of a factor \~ 2 above 1 TeV. The ANTARES sensitivity to diffuse neutrino flux models is obtained from an energy cut, rejecting most of the atmospheric neutrino background which has a softer spectrum. Fake upgoing events from downgoing atmospheric muons are rejected using dedicated variables. After 1 year of data taking, the ANTARES sensitivity is E^2 dF/dE < 8 10^-8 GeV cm^-2 s^-1 sr^-1 for a 10 string detector and an E^-2 diffuse flux spectrum.