Soon (fingers crossed), new neutrino telescopes might be able to discover ultra-high-energy (UHE) neutrinos, with energies above 100 PeV. Two unknown quantities that will be targeted are the UHE neutrino flux and the UHE neutrino-nucleon cross section. Their measurement is co-dependent: the number of neutrino-initiated events detected will depend on their product.

Yet, typically, when forecasting one, important assumptions are made about the other, either on their size, their dependence on neutrino energy, or both (for recent work, see, e.g., 2007.10334, 2204.04237, 2205.09763, 2210.03756). This may have cast existing forecasts in too optimistic a light and downplayed the real capabilities of UHE neutrino telescopes to deliver measurements unhampered by the above assumptions.

In a new paper led by Víctor Valera and co-authored by Olga Mena and I, we have shown that upcoming UHE neutrinos telescopes should be able to jointly measure the UHE neutrino spectrum and cross section, including its energy dependence, without assuming prior knowledge of either:

We gear our forecasts to the radio-detection of UHE neutrinos in the radio array of IceCube-Gen2. We test different prescriptions, and recommend using flexible parametrizations of the neutrino spectrum—not a power law—that are able to capture its features. We find loose targets for the detector energy and angular resolution that are compatible with present-day design considerations, about 10% per decade in shower energy and about 2° in zenith angle.

Read more at

Joint measurement of the ultra-high-energy neutrino spectrum and cross section
Victor B. Valera, Mauricio Bustamante, Olga Mena
2308.07709 astro-ph