Dynamical Dark Energy and a Tachyonic Neutrino Endpoint Signal from a Nambu-Jona-Lasinio Condensate.

This paper derives two near-term falsifiable predictions from the Tachyonic Neutrino Condensate (TNC) framework—a microscopically derived model based on a two-gap Nambu-Jona-Lasinio (NJL) Lagrangian for tachyonic Weyl fermions. Key Predictions: 1. The KATRIN tritium beta-decay spectrum follows a linear rise, d/d ² + ², with a best-fit tachyonic mass < 0. 26 eV. 2. The dark energy equation of state exhibits a non-monotonic hump-shaped deviation from w = -1 peaking at z^* 0. 41, with a CPL parameter wₐ = +0. 097. These predictions follow from a single NJL coupling matrix constrained by neutrino oscillation data and string coupling gₛ 0. 21, with no additional free parameters. A 1. 4σ tension exists with DESI+Planck+Pantheon+; 2. 8–3. 0σ tensions with DES-SN5YR and Union3 compilations are noted without softening. The results are compared against DESI DR2 and KATRIN 2024 data, identifying DESI Year 5 (2026) as the decisive test.