BWhat changed
CAST used a solar-tracking magnet to search for axion-to-photon conversion. A 2012 helium-buffer run improved limits in selected mass regions near 0.2 and 0.4 eV. Its 2013–2015 vacuum run found no significant excess and reported a 95% upper coupling limit of 0.66 × 10⁻¹⁰ GeV⁻¹ for masses below about 0.02 eV.
Scientific scope
CAST used a solar-tracking magnet to search for axion-to-photon conversion. A 2012 helium-buffer run improved limits in selected mass regions near 0.2 and 0.4 eV. Its 2013–2015 vacuum run found no significant excess and reported a 95% upper coupling limit of 0.66 × 10⁻¹⁰ GeV⁻¹ for masses below about 0.02 eV. Both results depend on the assumed solar axion flux and conversion model, detector backgrounds and a Bayesian posterior with a flat prior in the fourth power of the coupling. The helium and vacuum mass regions and datasets differ; neither result is an axion detection or an exclusion of all masses. The vacuum-run limit accounts primarily for statistical fluctuations; the authors estimate systematic effects below 10% rather than independently proving they vanish.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. Both results depend on the assumed solar axion flux and conversion model, detector backgrounds and a Bayesian posterior with a flat prior in the fourth power of the coupling. The helium and vacuum mass regions and datasets differ; neither result is an axion detection or an exclusion of all masses. The vacuum-run limit accounts primarily for statistical fluctuations; the authors estimate systematic effects below 10% rather than independently proving they vanish.
Contributors
- The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.
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