The ultra-high-energy neutrino-nucleon cross section: measurement forecasts for an era of cosmic EeV-neutrino discovery

Abstract

Neutrino interactions with protons and neutrons probe their deep structure and may reveal new physics. The higher the neutrino energy, the sharper the probe. So far, the neutrino-nucleon (νN) cross section is known across neutrino energies from a few hundred MeV to a few PeV. Soon, ultra-high-energy (UHE) cosmic neutrinos, with energies above 100 PeV, could take us farther. So far, they have evaded discovery, but upcoming UHE neutrino telescopes endeavor to find them. We present the first detailed measurement forecasts of the UHE νN cross section, geared to IceCube-Gen2, one of the leading detectors under planning. We use state-of-the-art ingredients in every stage of our forecasts: in the UHE neutrino flux predictions, the neutrino propagation inside Earth, the emission of neutrino-induced radio signals in the detector, their propagation and detection, and the treatment of backgrounds. After 10 years, if at least a few tens of UHE neutrino-induced events are detected, IceCube-Gen2 could measure the νN cross section at center-of-mass energies of $$ \sqrt{s} $$ s ≈ 10–100 TeV for the first time, with a precision comparable to that of its theory prediction.

High-energy and ultra-high-energy neutrinos: A Snowmass white paper

“…Sub-degree pointing resolution is needed to resolve the neutrino sky [97][98][99][100][101] while also reducing the systematic uncertainties on cross section [17,18,[102][103][104][105][106][107] and inelasticity measurements [19]. Resolving the neutrino sky will be important to search for BSM physics that causes anisotropies.…”

“…The flux sensitivity, energy resolution, and pointing resolution are all key parameters for measuring both the neutrino-nucleon cross section [17,18,[102][103][104][105][106][107] and inelasticity [19], complementary probes of deep inelastic scattering. Key to both is a large number of events [116].…”

“…Measurements in the TeV-PeV range are based on IceCube showers [18,122] and tracks [17]. Projected measurements at energies above 100 PeV [106] are based on 10 years of operation of the radio component of IceCube-Gen2, assuming a resolution in energy of 10% and a resolution in zenith angle of 2 • . Since the flux at these energies remains undiscovered, projections for the measurement of the cross section are for different flux predictions.…”

Point sources of ultra-high-energy neutrinos: minimalist predictions for near-future discovery

“…For this work, we adopt the IceCube-Gen2 effective volumes from Ref. [5], computed via simulations using the same tools as the IceCube-Gen2 Collaboration.…”

Double and multiple bangs at tau neutrino telescopes: A novel probe of sphalerons with cosmogenic neutrinos

“…This guarantees a new place to probe the Standard Model (SM) of particle physics and possible new physics beyond. However, general issues of its particle physics potential are the large SM background and systematic uncertainties of the initial neutrino flux [16,[47][48][49][50][51][52][53]. In such a case, new physics effects mostly manifest themselves indirectly by affecting the energy and angular distributions of tau events.…”