[Paper Review] High-energy atmospheric neutrinos

S. I. Sinegovsky, A. A. Kochanov+1 more|arXiv (Cornell University)|Oct 12, 2010

Astrophysics and Cosmic Phenomena4 references3 citations

TL;DR

This paper presents a new one-dimensional calculation of the high-energy atmospheric muon neutrino flux (10–10⁷ GeV) using hadronic interaction models QGSJET-II, SIBYLL 2.1, and KM, incorporating non-scaling inclusive cross-sections, rising inelastic hadron-nucleus cross-sections, and a non-power-law primary cosmic ray spectrum. The key result is a significant flux discrepancy—up to a factor of 1.8—between SIBYLL 2.1 and QGSJET-II predictions above 1 TeV, primarily driven by uncertainties in kaon production cross sections.

ABSTRACT

High-energy neutrinos, arising from decays of mesons that were produced through the cosmic rays collisions with air nuclei, form unavoidable background noise in the astrophysical neutrino detection problem. The atmospheric neutrino flux above 1 PeV should be supposedly dominated by the contribution of charmed particle decays. These (prompt) neutrinos originated from decays of massive and shortlived particles, $D^\pm$, $D^0$, $\bar{D}{}^0$, $D_s^\pm$, $Λ^+_c$, form the most uncertain fraction of the high-energy atmospheric neutrino flux because of poor explored processes of the charm production. Besides, an ambiguity in high-energy behavior of pion and especially kaon production cross sections for nucleon-nucleus collisions may affect essentially the calculated neutrino flux. There is the energy region where above flux uncertainties superimpose. A new calculation presented here reveals sizable differences, up to the factor of 1.8 above 1 TeV, in muon neutrino flux predictions obtained with usage of known hadronic models, SIBYLL 2.1 and QGSJET-II. The atmospheric neutrino flux in the energy range $10-10^7$ GeV was computed within the 1D approach to solve nuclear cascade equations in the atmosphere, which takes into account non-scaling behavior of the inclusive cross-sections for the particle production, the rise of total inelastic hadron-nucleus cross-sections and nonpower-law character of the primary cosmic ray spectrum. This approach was recently tested in the atmospheric muon flux calculations [1]. The results of the neutrino flux calculations are compared with the Frejus, AMANDA-II and IceCube measurement data.

Motivation & Objective

• To compute the high-energy atmospheric muon neutrino flux in the 10–10⁷ GeV range with improved physical modeling.
• To assess the impact of hadronic interaction models (QGSJET-II, SIBYLL 2.1, KM) on neutrino flux predictions.
• To evaluate uncertainties in the conventional and prompt neutrino fluxes due to primary cosmic ray spectrum models and hadronic interaction parameters.
• To compare model predictions with AMANDA-II and IceCube experimental data to constrain prompt neutrino contributions.
• To quantify the role of kaon production cross sections as a dominant source of flux uncertainty at high energies.

Proposed method

• Uses a 1D solution method (NS) for nuclear cascade equations in the atmosphere, accounting for non-scaling inclusive cross-sections and rising total inelastic hadron-nucleus cross-sections.
• Incorporates the Zatsepin-Sokolskaya (ZS) primary cosmic ray spectrum model (valid up to 100 PeV) and the GH parameterization for energies below 10⁶ GeV.
• Applies spectrum-weighted moments (z_pc) to compare hadronic model behavior, particularly for pion and kaon production.
• Computes neutrino fluxes from decays of π±, K±, and μ±, including contributions from three-body semileptonic decays (Kμ3) and muon decays.
• Uses the NS method validated in prior atmospheric muon flux calculations (kss08, kss09, sks10) for consistency.
• Performs zenith-angle-dependent flux calculations and compares results with AMANDA-II and IceCube data.

Experimental results

Research questions

• RQ1 How do different hadronic interaction models (QGSJET-II, SIBYLL 2.1, KM) affect predictions of the high-energy atmospheric muon neutrino flux?
• RQ2 What is the relative contribution of kaon production cross sections to the uncertainty in the conventional neutrino flux at energies above 1 TeV?
• RQ3 To what extent do uncertainties in the primary cosmic ray spectrum and composition influence the atmospheric neutrino flux predictions?
• RQ4 How do model predictions compare with experimental data from AMANDA-II and IceCube in the 100 TeV energy range?
• RQ5 Which prompt neutrino flux models (VZ, RQPM, QGSM, GGV) are consistent with the AMANDA-II upper limit on the diffuse neutrino flux?

Key findings

• The conventional muon neutrino flux predicted by SIBYLL 2.1 and QGSJET-II differs by up to a factor of 1.8 at energies above 1 TeV, primarily due to differences in kaon production cross sections.
• The QGSJET-II + GH model yields the lowest conventional neutrino flux at high energies, with E²φν = 1.11×10⁻⁸ cm⁻² sr⁻¹ GeV at 90° zenith angle and 100 TeV energy.
• At 100 TeV, the prompt neutrino flux predicted by the RQPM model (4.61×10⁻⁸ cm⁻² sr⁻¹ GeV) and QGSM model (1.22×10⁻⁸ cm⁻² sr⁻¹ GeV) are consistent with the AMANDA-II upper limit of 7.4×10⁻⁸ cm⁻² sr⁻¹ GeV.
• The VZ prompt neutrino flux (8.12×10⁻⁸ cm⁻² sr⁻¹ GeV) exceeds the AMANDA-II limit, suggesting it is inconsistent with current data.
• The atmospheric muon neutrino flux shows weak dependence on primary spectrum models between 10 and 10⁵ GeV, but strong dependence on hadronic interaction models at higher energies.
• The study confirms that kaon production is a more critical factor in neutrino flux uncertainty than in muon flux, despite their shared origin in hadronic cascades.