Galactic cold clouds constraints on sub-GeV DM and asteroid-mass PBHs
Abstract
We show that the ionization of molecular and atomic clouds provides a novel probe of dark matter scenarios producing low-energy e+e- pairs through annihilation, decay, or Hawking evaporation of primordial black holes. We derive constraints on MeV-scale dark matter with masses between ∼1 and $100$ MeV, as well as on primordial black holes in the mass range 1014--3×1017g. By modeling the propagation of electrons and positrons inside these clouds, we show that uncertainties in charged-particle transport constitute the main limitation of this method. Nevertheless, for the most physically motivated propagation scenarios, the resulting constraints remain competitive with the strongest bounds currently available. We also identify the cloud properties that maximize the sensitivity to dark matter-induced ionization and discuss how larger samples of clouds, together with improved modeling of cosmic-ray ionization and cloud structure, could substantially enhance the reach of this technique. Our results establish molecular and atomic cloud ionization as a promising and complementary probe of sub-GeV dark matter and evaporating primordial black holes.
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BibTeX
@misc{perez2026galactic,
title = {{Galactic cold clouds constraints on sub-GeV DM and asteroid-mass PBHs}},
author = {Asier Salces Pérez and Pedro de la Torre Luque},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.28823},
eprint = {2607.28823},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.28823},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Galactic cold clouds constraints on sub-GeV DM and asteroid-mass PBHs
AU - Asier Salces Pérez
AU - Pedro de la Torre Luque
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2607.28823
UR - https://arxiv.org/abs/2607.28823
AB - We show that the ionization of molecular and atomic clouds provides a novel probe of dark matter scenarios producing low-energy e^+e^- pairs through annihilation, decay, or Hawking evaporation of primordial black holes. We derive constraints on MeV-scale dark matter with masses between ∼1 and $100$ MeV, as well as on primordial black holes in the mass range 10^14--3×10^17g. By modeling the propagation of electrons and positrons inside these clouds, we show that uncertainties in charged-particle transport constitute the main limitation of this method. Nevertheless, for the most physically motivated propagation scenarios, the resulting constraints remain competitive with the strongest bounds currently available. We also identify the cloud properties that maximize the sensitivity to dark matter-induced ionization and discuss how larger samples of clouds, together with improved modeling of cosmic-ray ionization and cloud structure, could substantially enhance the reach of this technique. Our results establish molecular and atomic cloud ionization as a promising and complementary probe of sub-GeV dark matter and evaporating primordial black holes.
ER -