Review of Hubble tension solutions with new SH0ES and SPT-3G data

Abstract We present an updated analysis of eleven cosmological models that may help reduce the Hubble tension, which now reaches the 6σ level when considering the latest SH0ES measurement versus recent CMB and BAO data, assuming ΛCDM. Specifically, we look at five classical extensions of ΛCDM (with massive neutrinos, spatial curvature, free-streaming or self-interacting relativistic relics, or dynamical dark energy) and six elaborate models featuring either a time-varying electron mass, early dark energy or some non-trivial interactions in the neutrino sector triggered by a light Majoron. We improve over previous works in several ways. We include the latest data from the South Pole Telescope as well as the most recent measurement of the Hubble rate by the SH0ES collaboration. We treat the summed neutrino mass as a free parameter in most of our models, which reveals interesting degeneracies and constraints. We define additional metrics to assess the potential of a model to reduce or even solve the Hubble tension. We validate an emulator that uses active learning to train itself during each parameter inference run for any arbitrary model. We find that the time-varying electron mass and the Majoron models are now ruled out at more than 3σ. Models with a time-varying electron mass and spatial curvature or with early dark energy reduce the tension to 1.0-2.9σ. Nevertheless, none of the models considered in this work is favored with enough statistical significance to become the next concordance model of Cosmology.