Cosmological Implications of High-Energy Neutrino Emission from the Decay of Long-Lived Particle

TL;DR

This paper explores how the decay of long-lived massive particles in the early universe could produce high-energy neutrinos, potentially explaining IceCube's observations and constraining cosmological models.

Contribution

It provides a detailed calculation of neutrino spectra from particle decay, incorporating scattering effects, and derives new bounds from cosmic observations.

Findings

Decay of heavy particles can produce IceCube-like neutrino spectra.

Constraints from CMB and BBN limit the decay scenarios.

PeV neutrinos can originate from particles with masses up to 10^10 GeV.

Abstract

We study cosmological scenarios in which high-energy neutrinos are emitted from the decay of long-lived massive particles at the cosmic time later than a redshift of 10^6. The high-energy neutrino events recently observed by the IceCube experiment suggest a new source of high-energy cosmic-ray neutrinos; decay of a heavy particle can be one of the possibilities. We calculate the spectrum of the high-energy neutrinos emitted from the decay of long-lived particles, taking account of the neutrino scattering processes with background neutrinos. Then, we derive bounds on the scenario using the observation of high-energy cosmic-ray neutrino flux. We also study constraints from the spectral distortions of the cosmic microwave background and the big-bang nucleosynthesis. In addition, we show that the PeV neutrinos observed by the IceCube experiment can originate from the decay of a massive particle with its mass as large as O(10^10 GeV).