Testing CCC+TL Cosmology with Observed BAO Features

Abstract

The primary purpose of this paper is to see how well a recently proposed new model fits (a) the position of the baryon acoustic oscillations (BAO) features observed in the large-scale distribution of galaxies and (b) the angular size measured for the sound horizon due to BAO imprinted in the cosmic microwave background (CMB) anisotropy. The new model is a hybrid model that combines the tired light (TL) theory with a variant of the ${\Lambda}CDM$ model in which the cosmological constant is replaced with a covarying coupling constants' (CCC) parameter ${\alpha}$. This model, dubbed the CCC+TL model, can fit the supernovae type 1a Pantheon+ data as accurately as the ${\Lambda}CDM$ model, and also fit the angular size of cosmic dawn galaxies observed by the James Webb Space Telescope, which is in tension with the ${\Lambda}CDM$ model. The results we obtained are $151.0 (\pm5.1)$ Mpc for the absolute BAO scale at the current epoch, and the angular size of the sound horizon ${\theta}_{sh}=0.60{\deg}$ matching Planck's observations at the surface of the last scattering when the baryon density is set to 100% of the matter density and |${\alpha}$| is increased by 5.6%. It remains to be seen if the new model is consistent with the CMB power spectrum, the big-bang nucleosynthesis of light elements, and other critical observations.