# An algorithm for the reconstruction of high-energy neutrino-induced particle showers and its application to the ANTARES neutrino telescope

## TL;DR

This paper introduces a new algorithm for reconstructing neutrino-induced particle showers in the ANTARES telescope, achieving improved angular resolution and setting upper limits on astrophysical neutrino flux based on 6 years of data.

## Contribution

The paper presents a novel reconstruction algorithm for neutrino-induced showers in ANTARES, enhancing angular resolution and enabling new astrophysical neutrino flux constraints.

## Key findings

- Median angular resolution of 6° for energies below 100 TeV
- Observed 8 high-energy events over 6 years, consistent with atmospheric background
- Set a 90% CL upper limit on diffuse astrophysical neutrino flux

## Abstract

A novel algorithm to reconstruct neutrino-induced particle showers within the ANTARES neutrino telescope is presented. The method achieves a median angular resolution of $6^\circ$ for shower energies below 100 TeV. Applying this algorithm to 6 years of data taken with the ANTARES detector, 8 events with reconstructed shower energies above 10 TeV are observed. This is consistent with the expectation of about 5 events from atmospheric backgrounds, but also compatible with diffuse astrophysical flux measurements by the IceCube collaboration, from which 2 - 4 additional events are expected. A 90% C.L. upper limit on the diffuse astrophysical neutrino flux with a value per neutrino flavour of $E^2\cdot \Phi^{90\%} = 4.9 \cdot 10^{-8}$ GeV $\cdot$ cm$^{-2} \cdot$ s$^{-1} \cdot$ sr$^{-1}$ is set, applicable to the energy range from 23 TeV to 7.8 PeV, assuming an unbroken $E^{-2}$ spectrum and neutrino flavour equipartition at Earth.