A Combined Fit of the Diffuse Neutrino Spectrum using IceCube Muon Tracks and Cascades

TL;DR

This paper presents a new combined analysis of IceCube's 10-year neutrino data using the SnowStorm Monte Carlo method to improve understanding of the diffuse astrophysical neutrino flux and its spectrum.

Contribution

It introduces the novel SnowStorm method for systematic uncertainty modeling in a combined neutrino flux analysis, enhancing the accuracy of astrophysical neutrino flux measurements.

Findings

First combined analysis of muon tracks and cascades using SnowStorm.

Estimated sensitivities for the diffuse neutrino energy spectrum.

Improved constraints on the astrophysical neutrino flux model.

Abstract

The IceCube Neutrino Observatory first observed a diffuse flux of high energy astrophysical neutrinos in 2013. Since then, this observation has been confirmed in multiple detection channels such as high energy starting events, cascades, and through-going muon tracks. Combining these event selections into a high statistics global fit of 10 years of IceCube's neutrino data could strongly improve the understanding of the diffuse astrophysical neutrino flux: challenging or confirming the simple unbroken power-law flux model as well as the astrophysical neutrino flux composition. One key component of such a combined analysis is the consistent modelling of systematic uncertainties of different event selections. This can be achieved using the novel SnowStorm Monte Carlo method which allows constraints to be placed on multiple systematic parameters from a single simulation set. We will report on the status of a new combined analysis of through-going muon tracks and cascades. It is based on a consistent all flavor neutrino signal and background simulation using, for the first time, the SnowStorm method to analyze IceCube's high-energy neutrino data. Estimated sensitivities for the energy spectrum of the diffuse astrophysical neutrino flux will be shown.