A testable prediction: annular weak lensing ring at 100 kpc from toroidal dark matter halos

If dark matter halos have toroidal rather than spherical geometry, weak gravitational lensing around galaxies should exhibit an annular convergence ring at the torus major radius (Rmaj ≈ 100 kpc) — a signal that no spherically symmetric mass distribution can produce. We present a quantitative prediction for this signal and three independent tests using existing survey data: (i) face-on galaxy stacking (b/a > 0.8) should reveal an annular excess at R ≈ 100 kpc after NFW subtraction, detectable at raw 5σ with ∼7,046–9,981 face-on lenses from KiDS-1000 or DES-Y3 (post-look-elsewhere 5σ under Bonferroni T = 72 requires ∼9,442–13,374, the 1.34× inflation factor; Edri 2026b, Table 6); (ii) standard NFW fits to any stacked galaxy-galaxy lensing profile should show systematic negative excess surface mass density (ΔΣ < 0) at R ∼ 50–90 kpc, a signature impossible for monotonically decreasing profiles; (iii) NFW halo masses recovered from face-on galaxy stacks should be systematically lower than from edge-on stacks of matched true mass. If no annular residual is found across R ∈ [50, 200] kpc in ∼7,046 face-on KiDS-1000 galaxies under a template scan over Rmaj^tmpl (and, jointly, no γt sign change or negative-ΔΣ signature in mass-binned stacks), the toroidal halo geometry is falsified; a null only at the pre-registered Rmaj = 100 kpc anchor does not suffice, as it is degenerate with a systematic error in the rotation-curve-calibrated Rmaj. All three tests require no new observations — only reanalysis of existing public data.