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arXiv · 2609.27666

Energy estimation of direct and reflected cosmic-ray events aboard balloon-borne radio detectors

Sergio Cabana-Freire·Jaime Alvarez-Muñiz·Matias Tueros
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Abstract

Balloon-borne radio detectors offer a highly effective approach to monitoring immense volumes of the Earth's atmosphere and ice for ultra-high-energy cosmic rays and neutrinos. Because these payloads measure radio emission from a single, highly elevated vantage point, reconstructing the air-shower energy using traditional methods is not possible. In this work, we present a comprehensive, simulation-based energy reconstruction framework tailored to the unique cosmic-ray event geometries observed by balloon payloads. For the first time, we adapt and apply this methodology to direct atmosphere-skimming cosmic-ray showers, accounting for their highly asymmetric development in rarefied air. Furthermore, we provide a major update to the energy reconstruction of reflected downward-going showers by incorporating spherical reflection and ray de-focusing mechanics directly into simulations. We rigorously validate the method across different event geometries, demonstrating a baseline energy resolution of $8-11\%$. Finally, we quantify the systematic effects of finite detector pointing resolution, unknown primary mass composition, and signal-to-noise ratio, establishing a robust framework for the analysis of cosmic-ray events in next-generation balloon missions such as PUEO and POEMMA-Balloon with Radio.

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Sergio Cabana-Freire, Jaime Alvarez-Muñiz, Matias Tueros. 2026-09-23. Energy estimation of direct and reflected cosmic-ray events aboard balloon-borne radio detectors. https://arxiv.org/abs/2609.27666

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