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, ultrahigh-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 √ s ≈ 10-100 TeV for the first time, with a precision comparable to that of its theory prediction.

Neutrino Detection without Neutrino Detectors: Discovering Collider Neutrinos at FASER with Electronic Signals Only

“…In addition, there are several measurements using high energy cosmic neutrinos observed at IceCube which constrain the average ν µ + νµ cross sections at energies between 10 TeV and 10 PeV [69][70][71]. In the future, measurements with ultrahigh energy cosmic neutrinos will allow to extend these measurements to even higher energies [72].…”

Double and multiple bangs at tau neutrino telescopes

“…Unless very pessimistic flux predictions are chosen, the neutrino events will not be affected by orders of magnitude by adopting some popular flux choices; see, e.g., Ref. [51]. In general, with an observation of O(100) standard single-bang events, one would expect O(1) doublebang events, whereas the triple-bang rate is rather suppressed and negligible in light of the foreseeable programs.…”

“…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.…”

Design and Initial Performance of the Prototype for the BEACON Instrument for Detection of Ultrahigh Energy Particles

“…An exclusive measurement of the tau neutrino flux would yield both flux and flavor ratio information for testing both cosmogenic and astrophysical neutrino models [14,15]. Studying these UHE particles also provides a measurement of interaction cross sections at center-of-mass energies not achievable by current or planned collider experiments, and has the potential to reveal new physics [16][17][18][19].…”