What it takes to solve the Hubble tension through modifications of cosmological recombination [CEA]

http://arxiv.org/abs/2212.04494


We develop a novel general formalism allowing us to obtain values of the Hubble constant in agreement with late-time observables without degrading the fit to Cosmic Microwave Background data, considering perturbative modifications around a fiducial $\Lambda$CDM cosmology. Taking as proof-of-principle the case of a time-varying electron mass and fine structure constant, we demonstrate that a modified recombination can solve the Hubble tension and lower $S_8$ to match weak lensing measurements. Once baryonic acoustic oscillation and uncalibrated supernovae data are included, however, it is not possible to fully solve the tension with perturbative modifications to recombination.

Read this paper on arXiv…

N. Lee, Y. Ali-Haïmoud, N. Schöneberg, et. al.
Fri, 9 Dec 22
17/75

Comments: 5+11 pages, 2+10 figures