Spectral analysis of the high-energy IceCube neutrinos

Abstract

A full energy and flavor-dependent analysis of the three-year high-energy IceCube neutrino events is presented. By means of multidimensional fits, we derive the current preferred values of the high-energy neutrino flavor ratios, the normalization and spectral index of the astrophysical fluxes, and the expected atmospheric background events, including a prompt component. A crucial assumption resides on the choice of the energy interval used for the analyses, which significantly biases the results. When restricting ourselves to the ~30 TeV - 3 PeV energy range, which contains all the observed IceCube events, we find that the inclusion of the spectral information improves the fit to the canonical flavor composition at Earth, (1:1:1), with respect to a single-energy bin analysis. Increasing both the minimum and the maximum deposited energies has dramatic effects on the reconstructed flavor ratios as well as on the spectral index. Imposing a higher threshold of 60 TeV yields a slightly harder spectrum by allowing a larger muon neutrino component, since above this energy most atmospheric tracklike events are effectively removed. Extending the high-energy cutoff to fully cover the Glashow resonance region leads to a softer spectrum and a preference for tau neutrino dominance, as none of the expected electron antineutrino induced showers have been observed so far. The lack of showers at energies above 2 PeV may point to a broken power-law neutrino spectrum. Future data may confirm or falsify whether or not the recently discovered high-energy neutrino fluxes and the long-standing detected cosmic rays have a common origin.

33 pages, 13 figures. v3: one extra figure (fig. 13), some references updated and some formulae moved to the Appendix. It matches version published in PRD

References in corpus (56)

• Updated fit to three neutrino mixing: status of leptonic CP violation
• Neutrino oscillations refitted
• Calculation of atmospheric neutrino flux using the interaction model calibrated with atmospheric muon data
• Prompt neutrino fluxes from atmospheric charm
• Atmospheric and Astrophysical Neutrinos above 1 TeV Interacting in IceCube
• Flavor Composition and Energy Spectrum of Astrophysical Neutrinos
• Star-forming galaxies as the origin of diffuse high-energy backgrounds: Gamma-ray and neutrino connections, and implications for starburst history
• Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube
• Cosmic neutrino cascades from secret neutrino interactions
• Neutrinos from WIMP Annihilations Obtained Using a Full Three-Flavor Monte Carlo Approach
• Are both BL Lacs and pulsar wind nebulae the astrophysical counterparts of IceCube neutrino events?
• Neutrino Decays over Cosmological Distances and the Implications for Neutrino Telescopes
• Pinpointing Extragalactic Neutrino Sources in Light of Recent IceCube Observations
• IceCube PeV-EeV Neutrinos and Secret Interactions of Neutrinos
• Vetoing atmospheric neutrinos in a high energy neutrino telescope
• A Galactic Halo Origin of the Neutrinos Detected by IceCube
• On the flavor composition of the high-energy neutrino events in IceCube
• A generalized self-veto probability for atmospheric neutrinos
• IceCube events and decaying dark matter: hints and constraints
• Flavor Ratios of Astrophysical Neutrinos: Implications for Precision Measurements
• Energy dependent neutrino flavor ratios from cosmic accelerators on the Hillas plot
• Searching for Traces of Planck-Scale Physics with High Energy Neutrinos
• Which is the flavor of cosmic neutrinos seen by IceCube?
• Structured jets in BL Lac objects: efficient PeV neutrino factories?
• High-energy neutrinos from radio galaxies
• Mind the gap on Icecube: Cosmic neutrino spectrum and muon anomalous magnetic moment in the gauged L_μ - L_τ model
• What IceCube data tell us about neutrino emission from star-forming galaxies (so far)
• Glashow resonance as a window into cosmic neutrino sources
• The Direct Detection of Boosted Dark Matter at High Energies and PeV events at IceCube
• CνB absorption line in the neutrino spectrum at IceCube
• An Analysis of Cosmic Neutrinos: Flavor Composition at Source and Neutrino Mixing Parameters
• TANAMI Blazars in the IceCube PeV Neutrino Fields
• The diffuse gamma-ray flux associated with sub-PeV/PeV neutrinos from starburst galaxies
• Propagation of Superluminal PeV IceCube Neutrinos: A High Energy Spectral Cutoff or New Constraints on Lorentz Invariance Violation
• High energy neutrino yields from astrophysical sources I: Weakly magnetized sources
• Possible Interpretations of IceCube High-Energy Neutrino Events
• Galactic PeV neutrinos from dark matter annihilation
• Implications of a PeV neutrino spectral cutoff in GRB models
• Oscillation effects on high-energy neutrino fluxes from astrophysical hidden sources
• IceCube astrophysical neutrinos without a spectral cutoff and (10^15-10^17) eV cosmic gamma radiation
• Cosmological Implications of High-Energy Neutrino Emission from the Decay of Long-Lived Particle
• Neutrino Lighthouse at Sagittarius A*
• High-energy neutrino fluxes and flavor ratio in the Earth's atmosphere
• End of the cosmic neutrino energy spectrum
• Aspects of the Flavor Triangle for Cosmic Neutrino Propagation
• Estimating the contribution of Galactic sources to the diffuse neutrino flux
• Constraining Astrophysical Neutrino Flavor Composition from Leptonic Unitarity
• Cosmic Neutrino Flavor Ratios with Broken ${\nu }_{\mu }-{\nu }_{\tau }$ Symmetry
• Neutron β-decay as the origin of IceCube's PeV (anti)neutrinos
• Describing the Observed Cosmic Neutrinos by Interactions of Nuclei with Matter
• PeV-EeV neutrinos from GRB blastwave in IceCube and future neutrino telescopes
• Implications of Fermi-LAT observations on the origin of IceCube neutrinos
• Origin Of The High Energy Cosmic Neutrino Background
• A new physics interpretation of the IceCube data
• Leptonic CP violation at neutrino telescopes
• On the transport equations of cosmic neutrinos passing through Earth and secondary nu_mu fluxes

Cited by in corpus (9)

• Testing decay of astrophysical neutrinos with incomplete information
• Boosted Dark Matter in IceCube and at the Galactic Center
• Inferring the flavor of high-energy astrophysical neutrinos at their sources
• Sterile Neutrinos and Flavor Ratios in IceCube
• Probing decaying heavy dark matter with the 4-year IceCube HESE data
• Neutrino Oscillation in Dense Matter
• Neutrino lighthouse powered by Sagittarius A* disk dynamo
• Leptoquarks: 750 GeV Diphoton Resonance and IceCube Events
• The Flavour Composition of the High-Energy IceCube Neutrinos