Dark Matter via Quantum σ-Flip: Freeze-In at the QCD Transition and the Role of Gravitational Collapse

We propose a mechanism for dark matter (DM) production via stellar gravitational collapse based on a gauge quantum number σ = ±1 associated with a local U(1)_σ symmetry, mediated by a dark photon Z' of mass m_φ ~ 10 MeV. The symmetry is broken spontaneously at supernuclear densities (ρ ≥ ρ_nuclear ≈ 2.3 × 10^17 kg/m³, T_c ~ 10^12 K), triggering a σ-flip transition that converts visible-sector particles (σ = +1) into dark-sector fermions (σ = −1) of mass m_χ ~ MeV. This mass scale is cold enough to form structure consistent with observations, while the self-interaction cross-section σ/m ≈ 2.8 cm²/g (in the heavy-mediator Born limit) naturally resolves the core-cusp problem through Core+NFW halo profiles. The energy budget per supernova (E_SN ~ 3 × 10^46 J) supports M_DM ~ 1.5 × 10⁻⁴ M_☉ per event for efficiency ε_σ ~ 10⁻³, consistent with conservation laws. BBN compatibility is guaranteed since T_c ~ 10^12 K >> T_BBN ~ 10^9 K. Black holes are further proposed as informational transducers: at supercritical informational densities, photon-neutrino condensates undergo σ-flip, generating a linear M_BH–M_DM correlation testable by JWST and Euclid. Seven falsifiable predictions are derived for DUNE, Rubin LSST, Belle II, and gravitational wave observatories.