Caught by its own light: Wimpzillas, the LHAASO knee and the diffuse γ-ray sky
Abstract
We use the proton spectrum resolved by LHAASO across the knee to test superheavy dark matter in the nucleon channel at PeV energies. Both the hardening at $0.34$ PeV and the knee at $3.3$ PeV are reproduced by nucleons from a relic of mass 5· 107 GeV decaying in the Galactic halo, with the mass as the only shape parameter of the spectrum and the background index profiled under an independent prior on the proton slope below $0.1$ PeV. It works equally well in all three hadronic-interaction-model reconstructions. On the other hand, the photons of the same cascade rule out this interpretation by about two orders of magnitude against the photon fraction of the cosmic radiation, and by about one order of magnitude against the LHAASO diffuse Galactic emission.
Related
- A new view of the cosmic-ray knee after LHAASO
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- Statistical Modeling of Foreground Galactic Cirrus for Diffuse Halo Light Measurement
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- From DAMPE to LHAASO: Rigidity Scales and Composition Changes in Galactic Cosmic Rays
BibTeX
@misc{akl2026caught,
title = {{Caught by its own light: Wimpzillas, the LHAASO knee and the diffuse $γ$-ray sky}},
author = {D. Akl and A. J. Iovino and D. Kantzas and A. V. Macciò},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.17315},
eprint = {2609.17315},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17315},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Caught by its own light: Wimpzillas, the LHAASO knee and the diffuse γ-ray sky
AU - D. Akl
AU - A. J. Iovino
AU - D. Kantzas
AU - A. V. Macciò
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.17315
UR - https://arxiv.org/abs/2609.17315
AB - We use the proton spectrum resolved by LHAASO across the knee to test superheavy dark matter in the nucleon channel at PeV energies. Both the hardening at $0.34$ PeV and the knee at $3.3$ PeV are reproduced by nucleons from a relic of mass 5· 10^7 GeV decaying in the Galactic halo, with the mass as the only shape parameter of the spectrum and the background index profiled under an independent prior on the proton slope below $0.1$ PeV. It works equally well in all three hadronic-interaction-model reconstructions. On the other hand, the photons of the same cascade rule out this interpretation by about two orders of magnitude against the photon fraction of the cosmic radiation, and by about one order of magnitude against the LHAASO diffuse Galactic emission.
ER -