Neutrino Interactions at Ultrahigh Energies

TL;DR

This work refines ultrahigh-energy neutrino cross sections by updating parton distributions to CTEQ4-DIS and evaluating their uncertainties, particularly at very small x. It analyzes both neutrino-nucleon and neutrino-electron processes, including the W resonance, and translates cross sections into expected event rates for upward muons, contained events, and horizontal showers using diverse astrophysical flux models (AGNs, GRBs, top-down scenarios). The study finds cross sections are robust up to ~10^16 eV but increasingly uncertain at higher energies, with potential deviations offering insights into new physics or flux normalizations. Overall, the results indicate that km^3-scale detectors and Auger-like observatories could detect extraterrestrial neutrinos across several models, enabling constraints on high-energy cross sections and fluxes.

Abstract

We report new calculations of the cross sections for deeply inelastic neutrino-nucleon scattering at neutrino energies between $10^{9}\ev$ and $10^{21}\ev$. We compare with results in the literature and assess the reliability of our predictions. For completeness, we briefly review the cross sections for neutrino interactions with atomic electrons, emphasizing the role of the $W$-boson resonance in $\barν_{e}e$ interactions for neutrino energies in the neighborhood of $6.3\pev$. Adopting model predictions for extraterrestrial neutrino fluxes from active galactic nuclei, gamma-ray bursters, and the collapse of topological defects, we estimate event rates in large-volume water Čerenkov detectors and large-area ground arrays.

Figures (11)

• Figure 1: Cross sections for $\nu_{\ell} N$ interactions at high energies, according to the CTEQ4--DIS parton distributions: dashed line, $\sigma(\nu_{\ell} N \rightarrow \nu_{\ell}+\hbox{anything})$; thin line, $\sigma(\nu_{\ell} N \rightarrow \ell^{-}+\hbox{anything})$; thick line, total (charged-current plus neutral-current) cross section.
• Figure 2: Ratio of the charged-current cross section shown in Figure \ref{['fig:signuN4']}, calculated using the CTEQ4--DIS parton distributions, to the charged-current cross section of Ref. GQRS calculated using the CTEQ3--DIS parton distributions.
• Figure 3: Cross sections for $\bar{\nu}_{\ell}N$ interactions at high energies, according to the CTEQ4--DIS parton distributions: dashed line, $\sigma(\bar{\nu}_{\ell}N \rightarrow \bar{\nu}_{\ell}+\hbox{anything})$; thin line, $\sigma(\bar{\nu}_{\ell} N \rightarrow \ell^{+}+\hbox{anything})$; thick line, total (charged-current plus neutral-current) cross section.
• Figure 4: Cross sections for $\nu_{\ell}N$ interactions at high energies, according to the CTEQ4--HJ parton distributions: dashed line, $\sigma(\nu_{\ell} N \rightarrow \nu_{\ell}+\hbox{anything})$; thin line, $\sigma(\nu_{\ell} N \rightarrow \ell^{-}+\hbox{anything})$; thick line, total (charged-current plus neutral-current) cross section.
• Figure 5: Ratio of the charged-current cross section shown in Figure \ref{['fig:signuN4HJ']}, calculated using the CTEQ4--HJ parton distributions, to the charged-current cross section of Figure \ref{['fig:signuN4']} calculated using the CTEQ4--DIS parton distributions.