SKA-Mid Falsifiable Observables — Pre-Data Predictions

Pre-data SKA-Mid falsifiable predictions for the chameleon scalar-tensor framework. Four null tests: γ₁=0, Stokes V=0, EVPA Δθ=0, group delay τ=0. Δα/α~0.003–0.03 bonus prediction. Paper VI.

Four Null Tests (Paper VI, Zenodo 10.5281/zenodo.20146202)

All four predictions are registered before SKA-Mid data collection and are binary falsifiable: the framework is disproved if any null is violated.

  1. γ₁ = 0 — Stokes V null: Chameleon scalar coupling does not rotate circular polarisation. Any non-zero Stokes V detection above ISM baseline falsifies the framework.
  2. Stokes V = 0: Circular polarisation fraction null at Band 1–5 for all chameleon-candidate sources. Predicted upper limit: V/I < 10³.
  3. EVPA Δθ = 0 — rotation measure null: No anomalous EVPA gradient beyond Faraday rotation from known magnetic field structure. Falsification threshold: |Δθ| > 0.1 rad above ISM model.
  4. Group delay τ = 0 — dispersive delay null: No dispersive delay above ISM DM baseline at Band 1. Falsification: any frequency-dependent delay τ(ν) ≠ τ_ISM(ν) at 5σ.

Bonus Prediction

Δα/α ~ 0.003–0.03 — fine-structure constant drift along galactic sightlines where chameleon field is partially unscreened. Measurement: HI 21cm vs optical line ratios toward KBC void sightlines.

OH Gigamaser Calibration (Paper II)

Nkalakatha OH Gigamaser: GR baseline 1093.64 MHz → chameleon prediction 1095.04 MHz → measured 1095.07 ± 0.09 MHz. Residual −0.03 MHz (< 0.4σ). β = 0.734, D = 6.30 Gly. Pre-data prediction confirmed to < 0.4σ. Zenodo: 10.5281/zenodo.19422525.

NANOGrav Pulsar Timing (Paper LII)

Chameleon void-fraction correlation in post-GWB residuals. Predicted slope k·x_m = 1.92 · 0.026 = 0.050 yr/pc per unit |δ|. 20 MSPs. J1713+0747 + J1909-3744: Δt ~ 4.3–4.7 yr. Public data: Zenodo 8005193. Analysis: ~2 weeks.