From TeV to EeV: Characterization of the Cosmic Neutrino Flux with Combined Samples in IceCube

The IceCube Neutrino Observatory has detected astrophysical neutrinos from a few TeV to tens of PeV, and recent analyses have revealed deviations from a single power law at low energies, though statistical limitations have so far prevented resolving features at the PeV scale. A precise characterization of the neutrino spectrum across this range is essential to probe its connection to high-energy gamma rays in the low-energy regime and to ultra-high-energy cosmic rays (UHECRs) in the high-energy regime. To enhance sensitivity and leverage complementary information, we combine throughgoing tracks from the Northern Sky with high-energy starting tracks and both contained and uncontained cascades from the full sky. This analysis employs advanced atmospheric background modeling, refined ice systematics, and improved energy reconstruction through a hybrid of machine-learning and likelihood-based techniques.