Upper Limits on Hidden Mass in Cosmic Voids from DESI DESIVAST DR1: A Scale-Law Framework and Parity Test

We present the first systematic investigation of hidden mass in cosmic voids using the DESI DESIVAST DR1 void catalogue (Rincon et al. 2025), which contains 1, 478 voids identified by the VoidFinder algorithm in the DESI Year 1 Bright Galaxy Survey at z < 0. 24. We introduce a unified scale-law framework that parametrises the hypothetical mass of invisible galaxies in cosmic voids as Mᵥoid = Mᵣef × (Rᵥoid/Rᵣef) ⁿ, where n ∈ −1, 0, 1, 2, 3 encodes five physically motivated density profiles. We derive the minimum galaxy mass and number density required for each scaling law to account for the observed dark matter content of the observable universe. Applying a projected angular momentum estimator Lᵦ to 683 quality-selected voids with a 10, 000-iteration bootstrap, we obtain a parity signal of S/N = −0. 435σ (p = 0. 664), consistent with ΛCDM, and place the first upper limit on hidden-mass asymmetry in DESI voids: χ < 0. 06 at 95% CL. A pilot weak-lensing cross-correlation with 5 × 10⁶ KiDS DR3 galaxies yields κ = −0. 241 ± 0. 327 × 10⁻³ at the void centre, consistent with both ΛCDM and the hidden-mass prediction but insufficient to distinguish between the two scenarios. We derive the expected weak-lensing convergence κ for each scaling configuration, providing a falsifiable prediction for Euclid and Rubin/LSST observations.