Speaker
Description
Author: Stephan Meighen-Berger
Abstract: In this talk, we will discuss how upcoming kiloton-scale neutrino detectors, like Hyper-Kamiokande, can be used to measure the primary cosmic ray spectrum. Unlike traditional balloon or satellite missions that offer limited spatial and temporal coverage, large neutrino detectors provide full-sky monitoring over extended periods. By analyzing the atmospheric neutrinos produced in cosmic ray interactions, we show that these detectors can distinguish between competing models of the cosmic ray spectrum, even in the presence of uncertainties in neutrino cross sections and hadronic cascades. This is achieved by using a new method for reconstructing the primary cosmic ray spectrum from neutrino data, reducing flux uncertainties from ~20% to just 7%. This improved precision not only enhances our understanding of cosmic rays but also potentially boosts sensitivities of key neutrino studies, such as oscillation parameters. As an example, I will discuss a hypothetical sin²θ₂₃ measurement and how the reduction of the cosmic ray uncertainty can potentially double Hyper-K's precision. These results demonstrate how neutrino observatories are poised to play a central role in advancing both cosmic ray and neutrino physics.