Calculation of atmospheric neutrino flux using the interaction model calibrated with atmospheric muon data

TL;DR

The paper recalculates the atmospheric neutrino flux using a muon-data–calibrated modified DPMJET-III, with updated geomagnetic modeling and refined 3D/1D calculation merging to reduce systematic errors from virtual detectors. It tests robustness by applying muon-data–driven modifications to FLUKA'97 and Fritiof 7.02, highlighting that kaon production remains a major source of high-energy flux variation. The authors provide a quantified uncertainty budget, finding roughly 7% (1–10 GeV), 14% (100 GeV), and 25% (1 TeV) overall flux uncertainties, with the νμ/ν̄μ and ν_e/ν̄_e ratios stable at low energies and the angular dependence constrained to a few percent. They also supply detailed flux tables for multiple sites and energies, underscoring the impact of these uncertainties on neutrino-oscillation studies.

Abstract

Using the ``modified DPMJET-III'' model explained in the previous paper, we calculate the atmospheric neutrino flux. The calculation scheme is almost the same as HKKM04 \cite{HKKM2004}, but the usage of the ``virtual detector'' is improved to reduce the error due to it. Then we study the uncertainty of the calculated atmospheric neutrino flux summarizing the uncertainties of individual components of the simulation. The uncertainty of $K$-production in the interaction model is estimated by modifying FLUKA'97 and Fritiof 7.02 so that they also reproduce the atmospheric muon flux data correctly, and the calculation of the atmospheric neutrino flux with those modified interaction models. The uncertainties of the flux ratio and zenith angle dependence of the atmospheric neutrino flux are also studied.

Figures (12)

• Figure 1: Left panel: Ratio of all direction averaged flux with a smaller virtual detector ($\Phi_\nu(\theta_d=5^\circ)$) to that with the larger virtual detector ($\Phi_\nu(\theta_d=10^\circ)$) used in HKKM04. Right panel: Zenith angle ($\theta_z$) dependence of the ratio at $E_\nu=0.1$ GeV in azimuthal average.
• Figure 2: Left: Atmospheric neutrino fluxes for vertical directions calculated with the virtual detectors with different radii. Right: Ratio of fluxes calculated with virtual detectors with $\theta_d=10, 5,$ and $2.5^\circ$ to the flux estimated with Eq. \ref{['eq:estimation']}.
• Figure 3: The comparison of the atmospheric neutrino fluxes calculated with modified and original DPMJET-III in ratio. The denominator is the original DPMJET-III.
• Figure 4: The comparison of all direction average of the atmospheric neutrino fluxes with other calculations barr2004agrawal1995battis2002battis2003; (a) the absolute values of each kind of neutrinos and (b) the ratio of them.
• Figure 5: $Z$-factors for ${\pi^+} +{\pi^-}~(Z_\pi)$ and ${K^+} +{K^-}~(Z_K)$, and their ratio in each interaction model as the function of projectile energy. Solid lines are for DPMJET-III, dashed lines for FLUKA'97, and dotted lines for Fritiof 7.02.