Single seed b₃ = 24  →  axion at ma = 3.51 meV, gaγγ = 2.9 × 10⁻¹¹ GeV⁻¹  →  kill-shot test 2028

BabyIAXO (commissioning 2028) and full IAXO (~2030) will scan exactly this band. If the prediction is wrong, the framework collapses.

Live Prediction from parameters.json

ALP mass ma 3.510 meV
Photon coupling gaγγ 2.9 × 10⁻¹¹ GeV⁻¹
Source simulation abstract_v17_2
Status PREDICTED

Both values are loaded at page-load from /AutoGenerated/parameters.json (keys alp.mass_meV and alp.coupling_GeV_inv). They are derived from the topological seed b₃ = 24 — no free parameters.

Sensitivity Matrix

The PM prediction's central value and ±10% 1σ band against current and upcoming experimental reaches in the ALP–photon coupling plane.

Experiment Year Mass window ma Coupling floor gaγγ Verdict vs PM
PM prediction (central) 3.51 meV 2.9 × 10⁻¹¹ GeV⁻¹
PM 1σ band (±10%) 3.16 – 3.86 meV 2.61e-11 – 3.19e-11
CAST 2017 (current upper bound) 2017 ≲ 0.02 eV ≤ 6.6 × 10⁻¹¹ GeV⁻¹ PM allowed (below bound)
BabyIAXO Phase 1 2028 10⁻⁴ – 10⁻¹ eV ~1.5 × 10⁻¹¹ GeV⁻¹ ✓ REACHES PM band — kill-shot
IAXO (full) 2030+ 10⁻⁴ – 10 eV ~1.0 × 10⁻¹² GeV⁻¹ ✓ Buries the band — confirmation
ADMX (cavity haloscope) ongoing 2 – 40 μeV ~1 × 10⁻¹⁶ GeV⁻¹ Wrong mass regime — ADMX scans μeV cavity modes; 3.51 meV is ~100× too heavy for ADMX resonators
MADMAX (dielectric haloscope) ~2030 40 – 400 μeV target ~1 × 10⁻¹⁴ GeV⁻¹ Still developing; mass window roughly 10× too light, but planned extensions may approach the PM band

Kill criteria — what would falsify this prediction

BabyIAXO 2028+ will reach sensitivity gaγγ ≈ 1.5 × 10⁻¹¹ GeV⁻¹ for axion masses around 3.51 meV. Our prediction is gaγγ ≈ 2.9 × 10⁻¹¹ GeV⁻¹ at ma ≈ 3.51 meV — squarely within the discovery window.

What if BabyIAXO sees nothing?

A null result from BabyIAXO 2028 in the 3.16 – 3.86 meV mass window with gaγγ reach better than 2 × 10⁻¹¹ GeV⁻¹ would constitute a clean falsification — not an "amendment opportunity." The dependency chain b₃ = 24 → k → χeff → ma has no tunable slack. There is no quietly adjustable parameter we can twist to push the prediction outside the BabyIAXO band; the topological seed forces this exact coupling.

Outcomes

  • Confirmation: BabyIAXO detects an axion at gaγγ2.9 × 10⁻¹¹ GeV⁻¹, ma3.51 meV → theory CONFIRMED.
  • Falsification: BabyIAXO observes NO axion in the 1.5 × 10⁻¹¹ to 2 × 10⁻¹¹ GeV⁻¹ window across 3.16 – 3.86 meV → G₂ compactification ruled out.
  • Marginal: Axion detected at significantly different gaγγ (outside the 95% credible band) → theory needs amendment (e.g. revised χeff or Face-3 moduli normalisation).

Timeline

Milestones from today to first IAXO physics. The PM prediction is fixed — the experimental schedule is the only moving part.

2024 now 2026 construction 2028 BabyIAXO first physics (kill-shot run) 2030 full IAXO online (band buried) 2032 confirmation

2028 — BabyIAXO commissioning + first physics run reaches gaγγ ≈ 1.5 × 10⁻¹¹ GeV⁻¹ across 10⁻⁴ – 10⁻¹ eV.
2030 — full IAXO reaches ≈ 10⁻¹² GeV⁻¹, burying the PM band by an order of magnitude.

ma – gaγγ plane

Log–log plot of axion mass vs photon coupling. The PM prediction (pink point, ±10% errorbar) sits inside the BabyIAXO 2028 discovery region (green hatched) — visually demonstrating that BabyIAXO's first run is sufficient to falsify the framework.

Dependency chain — single seed to single observable

Every quantity on this page traces back to one topological input: the third Betti number of the G₂ manifold, b₃ = 24.

b₃ = 24 k = 12.318… χeff = 72 M27 → M⁴ vacuum residue ma = 3.51 meV
b₃ = 24 SEIS–photon coupling (Face 3 moduli) gaγγ ≈ 2.9 × 10⁻¹¹ GeV⁻¹

If BabyIAXO 2028 scans the 3.16 – 3.86 meV band and finds nothing, the chain breaks at its first link — the framework is falsified.

Coupling floors quoted are the standard BabyIAXO Phase 1 reach (Armengaud et al. 2019, JCAP 06:047) and the IAXO design report (CDR, 2014). PM 1σ band is conservative ±10%; actual uncertainty is dominated by k precision (better than 1%).