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arXiv · 2610.21495

Identification of ultra-high-energy neutrinos in vertical air showers with surface detectors

Jaime Alvarez-Muñiz·Ruben Conceição·Pedro J. Costa·David Dias·Mário Pimenta
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Abstract

We investigate the potential of surface detector arrays to identify ultra-high-energy neutrinos using vertical air showers with zenith angle $θ\leq 60^\circ$, a region largely unexplored in current searches. The method exploits the enhanced electromagnetic component at ground level arising from energetic leptons produced in neutrino interactions. Using detailed air-shower and detector simulations, we show that observables sensitive to the electromagnetic and muonic content provide genuine discrimination between neutrino-induced and hadron-induced showers. This is demonstrated both with idealized shower quantities and with realistic detector-level signals based on water-Cherenkov and scintillator detectors. The corresponding neutrino identification efficiency is used to derive the effective mass and, primarily, the effective area of the array under background-rejection requirements appropriate to targeted multi-messenger searches. Although not competitive with inclined-shower searches under the stringent background rejection factors required for diffuse-flux analyses, this approach establishes the feasibility of a vertical detection channel, extending the field of view of surface arrays and providing a complementary tool for multi-messenger observations of transient sources.

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Jaime Alvarez-Muñiz, Ruben Conceição, Pedro J. Costa, David Dias, Mário Pimenta. 2026-10-15. Identification of ultra-high-energy neutrinos in vertical air showers with surface detectors. https://arxiv.org/abs/2610.21495

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