The Oklo Natural Reactor Bound on the Fine-Structure Constant, Expressed as a Frame Coupling Limit
Year: 2026
Type: article
Abstract: Two billion years ago a uranium deposit in present-day Gabon sustained fission reactions, and the isotopic abundances it left behind record the energy of a neutron-capture resonance in samarium-149 at that epoch. Because the resonance energy is exquisitely sensitive to the fine-structure constant, the record bounds any change in alpha since then to between -9.00e-08 and 1.20e-07 (Damour and Dyson 1996). Averaged over the 1.8 billion year interval the upper edge corresponds to a mean rate of 6.67e-17 per year. Expressed against logarithmic accumulation with expansion, the bound limits the coupling to 8.86e-07. The reactor bound and the laboratory-clock bound are consistent, and each disciplines the other: the reactor integrates over deep time, the clocks measure the present slope. Computed from published inputs, not measured.
Author: Aldred, William Alexander
Language: English
Subfield: Statistical and Nonlinear Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225793302
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