Discrimination of muons for mass composition studies of inclined air showers detected with IceTop

TL;DR

This paper presents a method to distinguish muons from electromagnetic components in inclined air showers detected by IceTop, enabling primary cosmic-ray mass composition analysis at energies above 20 PeV.

Contribution

It introduces a charge and time-based muon discrimination technique for inclined air showers, improving primary mass categorization on an event-by-event basis.

Findings

Effective muon discrimination using charge and time cuts.

Ability to classify showers as light or heavy primaries.

Method applicable to high-energy inclined air showers.

Abstract

IceTop, the surface array of IceCube, measures air showers from cosmic rays within the energy range of 1 PeV to a few EeV and a zenith angle range of up to $\approx$ 36$^\circ$. This detector array can also measure air showers arriving at larger zenith angles at energies above 20 PeV. Air showers from lighter primaries arriving at the array will produce fewer muons when compared to heavier cosmic-ray primaries. A discrimination of these muons from the electromagnetic component in the shower can therefore allow a measurement of the primary mass. A study to discriminate muons using Monte-Carlo air showers of energies 20-100 PeV and within the zenith angular range of 45$^\circ$-60$^\circ$ will be presented. The discrimination is done using charge and time-based cuts which allows us to select muon-like signals in each shower. The methodology of this analysis, which aims at categorizing the measured air showers as light or heavy on an event-by-event basis, will be discussed.