Recent advances in data-driven modeling of cosmic ray and atmospheric lepton fluxes

Wednesday 4 Feb 2026, 16:30 → 18:30 Asia/Tokyo

A238 (Department of Physics, FAculty of Science, U. Toyama)

Accurate models of the cosmic ray spectrum and the fluxes of atmospheric muons and neutrinos provide essential inputs for interpreting astrophysical neutrino observations, neutrino oscillation studies, and investigating hadronic interaction models, as well as a wide range of applied fields, including muon tomography. In this talk, I will present our recent progress toward a fully data-driven and muon-calibrated description of atmospheric lepton fluxes. The daemonflux framework combines “foundation models” of the cosmic ray spectrum, numerical cascade calculations (MCEq), and hadronic interaction models with a global calibration procedure using muon flux and charge ratio measurements. I will highlight the latest update of the Global Spline Fit (GSF2025), a flexible cosmic ray flux parameterization covering energies from the GeV scale up to 100 EeV, and discuss how daemonflux predictions compare with underground muon measurements using the MUTE framework and demonstrate how these results enhance the description of recent KM3NeT muon data, achieving excellent agreement with observations and paving the way for precision atmospheric flux predictions.