Interpreting the KM3-230213A PeV Neutrino Event via Vector Dark Matter Decay and Its Multi-Messenger Signatures

TL;DR

This paper proposes a vector dark matter decay model to explain the ultra-high-energy neutrino event KM3-230213A, linking it to multi-messenger signals including gamma-rays and gravitational waves, and consistent with current observational constraints.

Contribution

It introduces a novel vector dark matter model with a $U(1)_X$ gauge symmetry that accounts for the neutrino event and predicts observable gravitational wave signatures.

Findings

Dark matter decay can explain the neutrino event within lifetime constraints.

The model predicts a stochastic gravitational wave background from cosmic strings.

Multi-messenger signals are consistent with current gamma-ray and pulsar timing array observations.

Abstract

The KM3NeT Collaboration recently reported the detection of an ultra-high-energy neutrino event KM3-230213A with a reconstructed energy of $220^{+570}_{-110}$ PeV, the most energetic astrophysical neutrino ever detected. The absence of convincing electromagnetic counterparts motivates exploration of exotic origins beyond standard astrophysical processes. We present a vector dark matter model based on a new $U(1)_X$ gauge symmetry to interpret this event through superheavy dark matter decay. Our analysis demonstrates that dark matter lifetimes in the range $7.3 \times 10^{28}$ to $2.9 \times 10^{30}$ s can successfully account for the KM3-230213A event while satisfying stringent constraints from gamma-ray observations. Moreover, the spontaneous breaking of $U(1)_X$ in our model naturally predicts cosmic string formation, generating a stochastic gravitational wave background with string tension $4.5 \times 10^{-11} \lesssim G\mu \lesssim 1.2 \times 10^{-10}$, consistent with recent pulsar timing array observations. This multi-messenger consistency across neutrinos, gamma-rays, and gravitational waves validates our vector dark matter interpretation of the KM3-230213A event while providing testable predictions for upcoming multi-wavelength experiments.