PreprintCC BY 4.0arXiv
Kaon Portal to Freeze-in Dark Matter
Abstract
We investigate freeze-in production of light dark matter through the quark flavor-changing operator (s̅γμd)(χ̅γμχ) in a low-reheating cosmology. For reheating temperatures below the QCD crossover, kaon decays and scatterings generate the dark matter abundance through K→πχχ̅ and Kπ→χχ̅. The same interaction induces the rare kaon decays K+→π+χχ̅ and KL→π0χχ̅. This links the freeze-in relic abundance to searches at NA62, KOTO, and KOTO II. We find that lower reheating temperatures require larger couplings to compensate for the Boltzmann-suppressed kaon abundance, making kaon-driven freeze-in dark matter testable at rare kaon decay experiments.
Versions
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BibTeX
@misc{endo2026kaon,
title = {{Kaon Portal to Freeze-in Dark Matter}},
author = {Motoi Endo and Takumu Yamanaka},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.05947},
eprint = {2605.05947},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.05947},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Kaon Portal to Freeze-in Dark Matter
AU - Motoi Endo
AU - Takumu Yamanaka
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2605.05947
UR - https://arxiv.org/abs/2605.05947
AB - We investigate freeze-in production of light dark matter through the quark flavor-changing operator (s̅γ_μd)(χ̅γ^μχ) in a low-reheating cosmology. For reheating temperatures below the QCD crossover, kaon decays and scatterings generate the dark matter abundance through K→πχχ̅ and Kπ→χχ̅. The same interaction induces the rare kaon decays K^+→π^+χχ̅ and K_L→π^0χχ̅. This links the freeze-in relic abundance to searches at NA62, KOTO, and KOTO II. We find that lower reheating temperatures require larger couplings to compensate for the Boltzmann-suppressed kaon abundance, making kaon-driven freeze-in dark matter testable at rare kaon decay experiments.
ER -