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Abstract In this work, we present the results of searches for signatures of dark matter decay or annihilation into Standard Model particles, and secret neutrino interactions with dark matter.Neutrinos could be produced in the decay or annihilation of galactic or extragalactic dark matter.Additionally, if an interaction between dark matter and neutrinos exists then dark matter will interact with extragalactic neutrinos.In particular galactic dark matter will induce an anisotropy in the neutrino sky if this interaction is present.We use seven and a half years of the High-Energy Starting Event (HESE) sample data, which measures neutrinos in the energy range of approximately 60 TeV to 10 PeV, to study these phenomena.This all-sky event selection is dominated by extragalactic neutrinos.For dark matter of ∼ 1 PeV in mass, we constrain the velocity-averaged annihilation cross section to be smaller than 10-23cm3/s for the exclusiveμ+μ-channel and 10-22cm3/s for the bb̅ channel.For the same mass, we constrain the lifetime of dark matter to be larger than 1028s for all channels studied, except for decaying exclusively to bb̅ where it is bounded to be larger than 1027s.Finally, we also search for evidence of astrophysical neutrinos scattering on galactic dark matter in two scenarios.For fermionic dark matter with a vector mediator, we constrain the dimensionless coupling associated with this interaction to be less than 0.1 for dark matter mass of 0.1 GeV and a mediator mass of 10-4GeV.In the case of scalar dark matter with a fermionic mediator, we constrain the coupling to be less than 0.1 for dark matter and mediator masses below 1 MeV.
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This content will become publicly available on October 1, 2026
Superheavy dark matter from the natural inflation in light of the highest-energy astroparticle events
Abstract Superheavy dark matter has been attractive as a candidate of particle dark matter. We propose a “natural” particle model, in which the dark matter serves as the inflaton in natural inflation, while decaying to high-energy particles at energies of 109-1013GeV from the prediction of the inflation. A scalar field responsible for diluting the dark matter abundance revives the natural inflation either with or without the recent data from the Atacama Cosmology Telescope (ACT) and baryon acoustic oscillation results from Dark Energy Spectroscopic Instrument.Since the dark matter must be a spin-zero scalar, we carefully study the galactic dark matter 3-body decay into fermions and two body decays into a gluon pair, and point out relevant multi-messenger bounds that constrain these decay modes. Interestingly, the predicted energy scale may coincide with the AMATERASU event and/or the KM3NeT neutrino event, KM3-230213A. We also point out particle models with dark baryon to further alleviateγ-ray bounds. This scenario yields several testable predictions for the UHECR observations, including the highest-energy neutrons that are unaffected by magnetic fields, the tensor-to-scalar ratio, the running of spectral indices,αs≳ 𝒪(0.001), and the existence of light new colored particles that could be accessible at future collider experiments.Further measurements of high-energy cosmic rays, including their components and detailed directions, may provide insight into not only the origin of the cosmic rays but also inflation.
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- PAR ID:
- 10652354
- Publisher / Repository:
- IOP Publishing Ltd and Sissa Medialab
- Date Published:
- Journal Name:
- Journal of Cosmology and Astroparticle Physics
- Volume:
- 2025
- Issue:
- 10
- ISSN:
- 1475-7516
- Page Range / eLocation ID:
- 109
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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