# Measurement of the $\nu_{\mu}$ energy spectrum with IceCube-79

## TL;DR

This paper presents a measurement of the muon neutrino energy spectrum using IceCube-79 data, revealing an excess at high energies and confirming compatibility with previous atmospheric and astrophysical neutrino flux measurements.

## Contribution

First measurement of the muon neutrino spectrum over a broad energy range with IceCube-79, utilizing machine learning for event classification and unfolding techniques.

## Key findings

- Spectrum covers 125 GeV to 3.2 PeV energies.
- Observed >1.9σ excess at energies ≥177.8 TeV.
- Results agree with previous atmospheric and astrophysical neutrino flux measurements.

## Abstract

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The $\nu_\mu$ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5\% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software \truee. The resulting spectrum covers an E$_\nu$-range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than $1.9\,\sigma$ in four adjacent bins for neutrino energies $E_\nu\geq177.8$\,TeV. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.