KM3-230213A and IceCube Neutrino Events from Metastable Dark Matter of Primordial Black Hole Origin

TL;DR

This work investigates whether ultra-high-energy neutrinos, including KM3-230213A and IceCube events, originate from the decay of metastable superheavy dark matter (DM) produced non-thermally by primordial black hole (PBH) evaporation. By enforcing the Planck relic abundance ${\Omega_{ m DM} h^2 \approx 0.12}$, the authors derive consistent constraints on the PBH abundance ${\beta}$ as a function of the initial PBH mass ${M_{ m BH_0}}$ and DM mass ${m_{\rm DM}}$, and compute the resulting DM-decay neutrino flux. They show that DM masses in the PeV–EeV range can yield neutrinos with energies compatible with both KM3-230213A and IceCube observations across a broad PBH-parameter region, without conflicting with cosmological bounds. The mechanism naturally evades stringent multimessenger constraints and remains viable for PBH masses ${M_{ m BH_0}}$ from about 10 g up to ${\sim 5\times10^{8}\text{ g}}$ and ${\beta}$ between ${10^{-30}}$ and ${10^{-14}}$, offering a testable link between early-universe PBH physics and present-day high-energy neutrino astronomy.

Abstract

We investigate a scenario in which the recently observed ultra-high-energy neutrino event KM3-230213A, with a median energy of approximately 220 PeV, as well as the high-energy neutrinos detected by IceCube Observatory, originate from the decay of superheavy dark matter (DM) particles produced through primordial black hole (PBH) evaporation. To establish this connection, we derive constraints on the PBH abundance parameter $β$ as a function of the initial PBH mass $M_{\mathrm{BH_0}}$ and DM mass $m_{\mathrm{DM}}$, by considering the bound from the observed relic DM abundance. Using these constraints, we compute the resulting neutrino flux and show that DM masses in the PeV-EeV range can yield neutrinos of comparable energies, capable of accounting for both the KM3-230213A and IceCube events while remaining consistent with the relic abundance constraint. Interestingly, the scenario remains viable over a broad region of parameter space while satisfying existing cosmological and astrophysical bounds. Overall, our results demonstrate that PBH evaporation followed by DM decay provides a consistent and natural explanation for the observed ultra-high-energy neutrino events in the absence of accompanying multimessenger signatures.

Figures (5)

• Figure 1: Constraints on the PBH abundance, $\beta$, as a function of the black hole mass $M_{\rm BH_0}$ and DM mass $m_{\rm DM}$, obtained in the radiation-dominated era using the observed relic abundance of DM from the Planck satellite, $\Omega_{\rm DM} h^2 = 0.12$. The white line corresponds to the critical abundance $\beta = \beta_c$. The region to the left of the white line represents the allowed parameter space in the $M_{\rm BH_0}$-$m_{\rm DM}$ plane for a given range of $\beta$ during the radiation-dominated era. The region to the right of the white line is not allowed.
• Figure 2: Phase-space distribution function of neutrinos produced from DM decay, shown for fixed values of the primordial black hole mass, DM mass, and the scale factor at which the decay occurs.
• Figure 3: The energy squared differential neutrino flux per steradian with respect to the energy of the neutrinos. Figure shows the neutrino flux dependence on the scale factor $a_d$ at which the dark matter is decaying at a constant mass of the dark matter $m_{DM} =5000\, {\rm PeV}$. The yellow shaded region, green and light blue region corresponds to the flux for $a_d = 10^{-3}, 10^{-2}$ and $10^{-1}$ respectively. The violet and red data points correspond to observed high-energy neutrino events from or 7.5 years of IceCube data and recent KM3NET respectively. The grey line is the quasi-differential upperbound on the extremely high-energy neutrino flux observations from 9 years of IceCube observations.
• Figure 4: The energy squared differential neutrino flux per steradian with respect to the energy of the neutrinos for a fixed $a_D = 0.01$. The yellow shaded region, green and light blue region corresponds to the flux for $m_{\rm DM} = 500~{\rm PeV}, 5000~{\rm PeV}$ and $50000$ PeV respectively. The violet and red data points correspond to observed high-energy neutrino events from or 7.5 years of IceCube data and recent KM3NET respectively. The grey line is the quasi-differential upper bound on the extremely high-energy neutrino flux observations from 9 years of IceCube observations.
• Figure 5: The neutrino flux as a function of PBH constituting the fraction of dark matter $f_{\rm DM}$ at fixed mass of the dark matter $m_{DM}=5000\, {\rm PeV}$ and scale factor at DM decay $a_d = 10^{-2}$.