EE/BB Decorrelation

In standard ΛCDM, the E-mode and B-mode polarization fields of the CMB are generated by distinct physical processes — scalar density perturbations produce only E-modes at the surface of last scattering, while primordial gravitational waves produce both E- and B-modes. The two fields should be statistically decorrelated by construction in the simplest models, with any EE-BB correlation arising only from weak gravitational lensing of E-modes into B-modes at low redshift. Observations find hints of residual EE/BB correlations at low multipoles that exceed the lensing-only prediction, suggesting either residual foreground contamination or a physical source of EE-BB mixing. In SCT, the angular momentum of the collision event provides exactly such a physical mixing source. The helical velocity field imprinted on the photon-baryon plasma by the collision angular momentum couples the scalar and tensor perturbation sectors, converting some of the E-mode power generated by density fluctuations into B-mode power through a rotation of the polarization pattern around the angular momentum axis.

This EE-to-BB conversion is concentrated at the angular scales corresponding to the collision geometry — primarily at low multipoles — and is antisymmetric under reversal of the angular momentum direction, meaning it also generates the TB and EB correlations discussed above. The EE/BB decorrelation tension, the TB/EB correlations, the parity-odd preference, and the hemispherical power asymmetry are therefore all manifestations of the same physical angular momentum field in SCT. A joint analysis of all four signals should find them consistently described by a single angular momentum vector whose direction, magnitude, and sense of rotation are mutually compatible — a highly specific and falsifiable prediction that distinguishes SCT's single-event angular momentum mechanism from multiple independent sources of foreground or systematic contamination.