The Highest-Energy Neutrino Event Constrains Dark Matter-Neutrino Interactions

Abstract

Dark Matter-neutrino interactions affect the propagation of astrophysical neutrinos, attenuating the flux of neutrinos arriving at Earth. Using the highest-energy neutrino event detected to date by the KM3NeT collaboration as an example, and assuming an extragalactic origin, we derive limits on these interactions at $E_ν= 220^{+570}_{-110}\, \mathrm{PeV}$. Considering only the propagation on the Milky Way Dark Matter halo, we constrain the interaction cross section over the mass of the Dark Matter candidate to be, $σ_{\rm DM-ν}/m_{\rm DM} \lesssim 10^{-22}\, \mathrm{cm}^2\,\mathrm{GeV}^{-1}$. If a transient source was positively identified, the high-energy neutrino would have crossed the dark-matter halo of the source host as well, resulting in more stringent constraints (e.g., up to $ \sim$ 6 orders of magnitude assuming the blazar PKS 0605-085 is the source). These bounds on the Dark Matter-neutrino interaction cross section are translated into limits on the mass of the Dark Matter candidate, the mass of the mediator, and the coupling strength for different simplified models. We find that the constraints from the KM3-230213A high-energy event for these simplified models are almost entirely ruled out for masses above the MeV by unitarity constraints. Therefore, the attenuation of such energetic neutrinos by Dark Matter calls for richer dark sectors in order to produce meaningful constraints.

Figures (4)

• Figure 1: Compilation of bounds on DM-neutrino scatterings across neutrino energies. A dark blue arrow indicates the exclusion limit from KM3-230213A assuming propagation only in the Milky Way, and lavender blue lines extrapolate it to lower energies, for $E_\nu^{-1}$ and a model with fermion DM and vector mediator, see Eq. \ref{['eq:xs-fermionvector']}. A light blue arrow indicates the strengthened constraints if the emission arises from a blazar such as PKS 0605-085. Our constraints are compared to the typical cross section hinted by various cosmological observables like Ly-$\alpha$, $H_0$ and $S_8$Hooper:2021rjcDiValentino:2017oaw (orange), constraints from Milky-Way Satellites Crumrine:2024sdn (red), bounds from supernova SN1987A Mangano:2006mpChauhan:2025hoz (light green), the diffused neutrino flux from DM-neutrino scatterings for galactic supernovae Chauhan:2025hoz (dark green), bounds from TXS 0506+056 Ferrer:2022keiCline:2022qldZapata:2025huq (grey), and from the diffuse flux of astrophysical neutrinos Arguelles:2017atb (brown).
• Figure 2: Left panel: Upper limits on the product of gauge couplings of a new vector mediator to the DM Dirac fermion and neutrinos versus DM mass. We show the limits from KM3-230213A derived in this work as shaded contours. The dark blue contour consider attenuation only in the Milky Way, whereas light blue contour assumes the emission arises from PKS 0605-085. The light blue dashed lines indicates the limit from TXS 0506+056 Ferrer:2022keiCline:2022qldZapata:2025huq. For comparison, we show the region of parameter space where the cross-section exceeds unitarity constraints (gray dot-dashed line), the observed relic abundance of DM can be achieved (red dotted line) and the limits on DM annihilation (green dashed line) Arguelles:2019ouk. Right panel: Same as the left panel, but for the vector DM with a vector mediator case.
• Figure 3: Sky map of the DM column density of the Milky Way's halo, $\Sigma_{\rm DM}$, for the DM profile used in this work, together with the location of KM3-230213A event and the 99% (dotted) and 68% (dashed) uncertainty regions.
• Figure 4: Upper limits on the product of gauge couplings of a new vector mediator to the DM Majorana fermion and neutrinos (left) and on the product of gauge couplings of a new vector mediator to the DM scalar and neutrinos (right) versus DM mass. We show the limits from KM3-230213A derived in this work as shaded contours. The dark blue contour consider attenuation only in the Milky Way, whereas light blue contour assumes the emission arises from PKS 0605-085. The light blue dashed lines indicates the limit from TXS 0506+056 Ferrer:2022keiCline:2022qldZapata:2025huq.For comparison, we show the region of parameter space where the cross-section exceeds unitarity constraints (gray dot-dashed line), the observed relic abundance of DM can be achieved (red dotted line) and the limits on DM annihilation (green dashed line) Arguelles:2019ouk.