Superheavy dark matter and stepped dark radiation for Hubble Tension
Year: 2026
Type: preprint
Abstract: Manuscript and CSV data behind the figure and table of Xu (2026), Superheavy dark matter and stepped dark radiation for Hubble Tension, Research Square preprint, doi:10.21203/rs.3.rs-8570078/v3. The earlier data record of this work is zenodo.org/records/23001771. Contents: the manuscript (P05_revised.pdf) and the folder csv/ with the plotted data of Fig. 2 (free-streaming mass against particle mass) and the component densities of Table 1. Companion dataset: the cold freeze-out paper, Xu (2025), Eur. Phys. J. C 85, 1451, doi:10.1140/epjc/s10052-025-15180-z, data record doi:10.5281/zenodo.23934750. Major findings: The free-streaming mass equals the particle mass at m_Xc = 1.6×10-15 kg = 0.9×1012 GeV. A two-body gravitational bound state of 1012 GeV particles has a size of 1.2×10-13 m, an internal speed of 5×10-7 m/s and forms at tX = 5×10-7 s (T ≈ 1 GeV). The gravity-induced bulk velocity of dark matter is frozen during radiation domination at 8–9 km/s. Cold freeze-out leaves a relic fraction γ ≈ 10-9 (8×10-10 for 1012 GeV); ΔNeff = 0.4 needs a dark-radiation share fDR ≈ 0.2 of the converted energy. In the stepped dark-radiation embedding, the measured drag RΓ = 0.07 gives a DM–DR Yukawa coupling λX ≈ 8×10-5; a Planck-suppressed portal gives yK ≈ 7×10-15 and a no-scale supergravity scalar mass of about 0.5 eV. Gravitational production with γ ≈ 10-8 needs HI ≈ 1012 GeV, TRH ≈ 1015 GeV and a tensor-to-scalar ratio r ≈ 2×10-5.
Author: Xu, Zhijie (Jay)
Institution: Pacific Northwest National Laboratory
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225626020
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