Superheavy dark matter data and manuscript: cold freeze out and Hubble tension

Manuscript and CSV data behind the figures and tables of Xu (2025), Cold freeze out of superheavy dark matter and Hubble tension, Eur. Phys. J. C 85, 1451, doi:10.1140/epjc/s10052-025-15180-z, arXiv:2202.07240. Contents: the manuscript (manuscript.pdf) and csv/ (34 CSV files: the plotted data of the figures, the tables, and the result sets of the checks). Companion datasets: Dataset Part I (halo-based), 10.5281/zenodo.6541231; Dataset Part II (correlation-based), 10.5281/zenodo.6757654; all files, 10.5281/zenodo.6586213. Major findings: A superheavy dark matter particle of mass mX ≈ 1012 GeV, with size rX = 4ħ²/(GmX3) ≈ 10-13 m, is found by three routes: the free-streaming scale, an "X miracle" analogous to the WIMP miracle, and the scaling laws of dark matter haloes. Particles of this mass can form the earliest and smallest gravitationally bound structures at tX ≈ 10-6 s after the Big Bang, and the annihilation or decay in these structures leads to a "cold" freeze out. The solutions of the Boltzmann equation show a large depletion, with about one particle in 108 surviving as today's dark matter, which gives an additional radiation contribution ΔNeff ≈ 0.3–0.4 that could help alleviate the Hubble tension. For 1012 GeV particles the dark coupling constant is αX ≈ 0.09, and the instanton-induced decay is consistent with current UHECR bounds. The early collapse can release binding energy as gravitational waves of about 100 kHz or as ultralight GUT-scale axions of about 10-9 eV. Superheavy sterile neutrinos are a natural particle realization that links dark matter to neutrino mass and baryogenesis.