Cosmological parameters from Planck data in SU(2)$_{\rm CMB}$, their local $Λ$CDM values, and the modified photon Boltzmann equation

Abstract: A review of the spatially flat cosmological model SU(2)${\rm CMB}$, minimally induced by the postulate that the Cosmic Microwave Background (CMB) is subject to an SU(2) rather than a U(1) gauge principle, is given. Cosmological parameter values, which are determined from the Planck CMB power spectra at small angular scales, are compared to their values in spatially flat $\Lambda$CDM from both local and global extractions. As a global model SU(2)${\rm CMB}$ leans towards local $\Lambda$CDM cosmology and is in tension with some global $\Lambda$CDM parameter values. We present spectral antiscreening / screening effects in SU(2)${\rm CMB}$ radiance within the Rayleigh-Jeans regime in dependence on temperature and frequency. Such radiance anomalies can cause CMB large-angle anomalies. Therefore, it is pointed out how SU(2)${\rm CMB}$ modifies the Boltzmann equation for the perturbations of the photon phase space distribution at low redshift and why this requires to the solve the $\ell$-hierarchy on a comoving momentum grid ($q$-grid) for all $z$.