The spectrum of the light component of TeV cosmic rays measured with HAWC

TL;DR

This paper measures the energy spectrum of light cosmic ray components (protons and helium) between 10 TeV and 200 TeV using HAWC, filling a gap between direct and indirect measurements with a large dataset and advanced analysis techniques.

Contribution

It provides the first detailed spectrum of light cosmic rays in the 10-200 TeV range using HAWC data with a novel unfolding and mass selection method.

Findings

Spectrum of light cosmic rays measured from 10 to 200 TeV.

Large dataset of 3.8 billion air shower events analyzed.

Effective separation of light and heavy components achieved.

Abstract

We present a measurement of the energy spectrum of the light mass group of cosmic rays (protons and helium) with the High Altitude Water Cherenkov (HAWC) Observatory in the energy interval from $10$ TeV to $200$ TeV. The spectrum covers the energy range between direct and indirect measurements, where precision data on the composition of cosmic rays are needed. The spectrum was constructed by applying an unfolding technique on a proton plus helium enriched sub-sample ($>90\%$ abundance) of cosmic ray air showers selected from the HAWC cosmic-ray data. The subset contains $3.8 \times 10^{9}$ air shower events with primary energies in the interval $1$ TeV to $300$ TeV and zenith angles less than $16.7$ degrees. Mass selection was performed using an analysis of the lateral age parameter of air shower events, based on both CORSIKA/QGSJET-II-03 simulations and event-by-event measurements on the lateral structure of the shower front and the primary energy of the showers.