Neutrino Structure Functions from GeV to EeV Energies

TL;DR

This paper develops a comprehensive method to accurately predict neutrino-nucleus scattering across a wide energy range, combining machine learning and pQCD, crucial for current and future neutrino experiments.

Contribution

It introduces the NNSFν approach, integrating machine learning with pQCD to determine neutrino structure functions from GeV to EeV energies, improving upon existing models.

Findings

Provides a unified neutrino structure function determination covering all relevant energies.

Offers updated cross section predictions for various target nuclei and energies.

Delivers accessible LHAPDF grids and tools for neutrino event simulation.

Abstract

The interpretation of present and future neutrino experiments requires accurate theoretical predictions for neutrino-nucleus scattering rates. Neutrino structure functions can be reliably evaluated in the deep-inelastic scattering regime within the perturbative QCD (pQCD) framework. At low momentum transfers ($Q^2 \le {\rm few}$ GeV$^2$), inelastic structure functions are however affected by large uncertainties which distort event rate predictions for neutrino energies $E_\nu$ up to the TeV scale. Here we present a determination of neutrino inelastic structure functions valid for the complete range of energies relevant for phenomenology, from the GeV region entering oscillation analyses to the multi-EeV region accessible at neutrino telescopes. Our NNSF$\nu$ approach combines a machine-learning parametrisation of experimental data with pQCD calculations based on state-of-the-art analyses of proton and nuclear parton distributions (PDFs). We compare our determination to other calculations, in particular to the popular Bodek-Yang model. We provide updated predictions for inclusive cross sections for a range of energies and target nuclei, including those relevant for LHC far-forward neutrino experiments such as FASER$\nu$, SND@LHC, and the Forward Physics Facility. The NNSF$\nu$ determination is made available as fast interpolation LHAPDF grids, and can be accessed both through an independent driver code and directly interfaced to neutrino event generators such as GENIE.