Cosmic Ray Results from the IceTop Air Shower Array

TL;DR

This paper presents initial findings from IceTop, a surface array at the South Pole, measuring cosmic ray energy spectrum and composition between 1 PeV and 80 PeV, highlighting the detector's sensitivity to primary mass.

Contribution

It introduces the first results from IceTop on cosmic ray spectrum and composition, demonstrating the detector's capability to distinguish primary particle types through zenith angle analysis.

Findings

Different spectra for protons and iron nuclei at various angles

Mixed composition models align with isotropic flux expectations

Potential for enhanced composition measurements with IceCube

Abstract

We report on the first results obtained with the IceTop air shower array on the cosmic ray energy spectrum and mass composition in the range of 1 PeV to 80 PeV. IceTop is the surface detector of the IceCube neutrino telescope currently under construction at the South Pole. A high sensitivity to the primary mass composition was observed by reconstructing showers at different zenith angles. Assuming only protons or iron nuclei as primary particles yields significantly different energy spectra for different zenith angle ranges, while only models with mixed composition, like the poly-gonato model, lead to the expected isotropic flux. The prospects of composition measurements with different, alternative methods using the full IceCube detector are also discussed.