The CMB polarization power spectrum exhibits an unexpected enhancement or bump at intermediate angular scales not well-explained by ΛCDM's predictions for how polarization scales with temperature anisotropies and Thomson scattering during reionization (Planck 2018; Hazumi 2020). Standard reionization models predict a smooth single-epoch polarization signal; the observed bump suggests either more complex reionization history or additional polarization sources.
The standard model assumes a single smooth reionization epoch around z ≈ 6 to 8 produced by the first stars. Under that assumption, the polarization spectrum shape is determined by one optical-depth parameter and one redshift, and a localized intermediate-scale enhancement has no source in the model. Adding sufficient optical depth to fit the bump creates tension with 21-cm constraints and early-galaxy surveys.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, reionization is naturally multi-phase rather than a single smooth epoch. The cascade ends well before t ≈ 1 second (P40), but post-cascade reheating events (P47) operate during the cosmological era between cascade termination and the era when first stars become numerous. Each reheating event can re-ionize localized regions at staggered times, producing additional polarization signal at scales matching the reheating-event coherence length.
The Plasma Equivalence Theorem (P29, P30) ensures the bulk polarization spectrum at l > 30 reproduces ΛCDM precisely; the deviation from ΛCDM appears as an intermediate-scale bump where the multi-phase reionization signal layers on top of the standard signal. The bump amplitude scales with the cumulative reheating contribution; its scale is set by the typical coherence radius of reheating events; its position in the polarization spectrum aligns with the angular scale corresponding to those reheating-event sizes (cross-link to recid 170, recid 180 for the multi-phase reionization predictions).
The same M2 framework that resolves the bulk acoustic-peak structure (recid 25) accommodates the polarization-bump anomaly through the multi-phase reionization that follows from cascade-cycle dynamics. There is no need to invoke exotic polarization sources or fine-tuned single-epoch reionization that conflicts with 21-cm constraints. The bump is one more observational window onto SCT's prediction that reionization is not a single smooth event.
If LiteBIRD or CMB-S4 confirm the polarization bump is fully reproduced by a single-epoch smooth reionization at high precision (no multi-phase structure required), the M2 multi-phase reheating contribution is refuted. Equivalently, if 21-cm tomography (HERA, SKA) finds reionization proceeded smoothly from a single-redshift onset rather than in distinct phases, the SCT multi-phase prediction fails.