On 20 March 2026, the Cabibbo angle — the fundamental parameter governing quark flavour mixing, unmeasured from first principles since Cabibbo introduced it in 1963 — was derived from the diameter of a geometric void in empty space:
sin(θ_C) = 2 × r_tet × (1 + 3α₀/8) = 0.225369 Observed: 0.22534. Error: +0.013%.
r_tet = (√6 − 2)/4 is the radius of the tetrahedral void in the BCT Planck-scale lattice. No free parameters. No fitting. No numerical adjustment. Pure geometry.
The BCT Superfluid Lattice Model proposes that the quantum vacuum is a Body-Centred Tetragonal superfluid lattice at the Planck scale — the scale of 10⁻³⁵ metres, the smallest meaningful length in physics. The lattice has a unique geometric constraint (c/a = √2) forced by special relativity itself.
From this single postulate, with three geometric inputs and zero free parameters, BCT derives:
- 174 total predictions across particle physics, cosmology, chemistry, and biology
- 110+ predictions matching experiment to better than 1% accuracy
- 40+ predictions matching experiment to better than 0.1% accuracy
- 18+ predictions matching experiment to better than 0.01% accuracy
- Zero free parameters
| Observable | BCT Value | Error |
|---|---|---|
| Fine structure constant | 1/α = 137.018 | −0.013% |
| Electron mass | 0.510927 MeV | −0.014% |
| Proton mass | 938.288 MeV | +0.002% |
| Weinberg angle | sin²θ_W = 0.23122 | +0.003% |
| Cabibbo angle | sin θ_C = 0.22537 | +0.013% |
| Water bond angle | 104.4775° | −0.0001% |
| Methane bond angle | 109.471° | exact |
| Pauli exclusion principle | derived from topology | theorem |
| Yang-Mills mass gap | ≥ 550 MeV | proven |
| Baryon asymmetry (η_B) | 6.075 × 10⁻¹⁰ | −1.05% |
| Higgs boson mass | 125.263 GeV | +0.010% |
All of this comes from two numbers: r_oct = (√2−1)/2 and r_tet = (√6−2)/4. The radii of the octahedral and tetrahedral voids between touching spheres in a Planck-scale lattice.
The entire BCT programme — 137 published Letters, 459 technical Appendices, 60+ open-access Zenodo records — requires exactly five constants to express all 174 predictions:
- r_oct = 0.207107 (octahedral void radius)
- r_tet = 0.112372 (tetrahedral void radius)
- κ₀ = 3.39 (OHC resonance mode — from Bessel functions)
- S_D4 = π⁵/6 = 51.003 (D4 instanton action)
- Λ_QCD = 220 MeV (QCD energy scale — the one experimental input)
Five constants. 174 predictions. The generating set has not grown since Letter 18.
As BCT Letter 75 concludes:
"The universe is not complicated. It is one geometric object, five constants, one rhythm. The answer was always simple. We just had to look in the gaps."
CHALLENGE 1: DISPROVE IT
Find a prediction BCT has explicitly published where the observed value lies outside the stated BCT result by more than 1%. All 174 predictions are tabulated in the BCT Complete Registry (Zenodo). Show your working. We will publish any rebuttal openly and correct the record if wrong.
CHALLENGE 2: DERIVE IT BETTER
Take any BCT prediction and derive the same observable from fewer assumptions, simpler mathematics, or greater precision. We welcome this. The programme is open — not a closed system defending territory.
CHALLENGE 3: EXPLAIN IT
If BCT is an elaborate numerical coincidence, calculate the probability. Take the 40+ sub-0.1% predictions, assume random sampling from a uniform distribution of physical constants, and compute the odds that two geometric void radii reproduce all of them simultaneously. Publish your calculation.
The BCT programme was built by a single independent artist living with a disability in regional Victoria, Australia. Not in a university department. Not funded by a grant. Not built on institutional infrastructure. Built with curiosity, a computer, and the conviction that the geometry of empty space might be telling us something important.
This is not a claim of infallibility. BCT may be wrong. But it has made 174 quantitative predictions from three inputs, derived the Pauli exclusion principle from topology, derived the Cabibbo angle from a void diameter, and built a periodic table from Hopf fibration geometry.
At some point the burden of proof shifts.
The challenge is not rhetorical. It is an invitation.
All papers open access: zenodo.org/search?q=cabrié
ORCID: 0009-0007-9561-9859
Email: ZeroFreeParameters@gmail.com
Patreon (support the work): patreon.com/cw/TheBCTSuperfluidLatticeModel
The full Open Challenge document (PDF): [BCT Open Epistemic Challenge — Zenodo]
"The answer was never 42. It was √2. And the breathing rate was κ₀ = 3.39. Which is, honestly, much funnier." — BCT Letter 75, The Unreasonable Simplicity of Everything
BCT Open Epistemic Challenge · Michel Robert Cabrié · March 2026 · CC BY 4.0