Heavy decaying dark matter and IceCube high energy neutrinos

TL;DR

This paper investigates whether decaying heavy dark matter could explain IceCube's high-energy neutrino observations, analyzing decay channels, mass ranges, and compatibility with gamma-ray constraints, and discusses future observational tests.

Contribution

It provides a comprehensive simulation of decay cascades and explores parameter space where leptonic dark matter decays fit IceCube data without conflicting gamma-ray limits.

Findings

Leptonic decay channels can explain IceCube neutrinos for specific mass ranges.

Hadronic decays generally conflict with gamma-ray observational limits.

Upcoming gamma-ray observatories can test significant parts of the proposed parameter space.

Abstract

We examine the hypothesis of decaying heavy dark matter (HDM) in the context of the IceCube highest energy neutrino events and recent limits on the diffuse flux of high-energy photons. We consider dark matter (DM) particles $X$ of mass $10^{6}\leq M_X\leq~10^{16}$ GeV decaying on tree level into $X \rightarrow \nu \bar{\nu}$, $X \rightarrow e^+e^-$ and $X \rightarrow q \bar{q}$. The full simulation of hadronic and electroweak decay cascades and the subsequent propagation of the decay products through the interstellar medium allows us to determine the permitted values of $M_X$. We show that for leptonic decay channels it is possible to explain the IceCube highest energy neutrino signal without overproducing high-energy photons for $M_X~\lesssim~5.5 \cdot 10^{7}$ GeV and $1.5 \cdot 10^{8}~\lesssim~M_X~\lesssim~1.5 \cdot 10^{9}$ GeV, while hadronic decays contradict the gamma-ray limits for almost the whole range of $M_X$ values considered. The leptonic hypothesis can be probed by operating and planned gamma-ray observatories. For instance, the currently upgrading Carpet experiment will be capable to test a significant part of the remaining parameter window within one year of observation.