Is there concordance within the concordance $\Lambda$CDM model?

TL;DR

This paper introduces a rigorous statistical test to measure the agreement between cosmological data sets within the $\\Lambda$CDM model, revealing overall concordance but highlighting significant tension between certain measurements like Planck CMB data and CFHTLenS weak lensing.

Contribution

It presents a novel statistical indicator for assessing data set concordance in cosmology, avoiding reliance on marginal posterior distributions.

Findings

High concordance among most cosmological data sets.

Significant tension between Planck CMB measurements and CFHTLenS weak lensing data.

Potential implications for systematic errors or new physics.

Abstract

We use a complete and rigorous statistical indicator to measure the level of concordance between cosmological data sets, without relying on the inspection of the marginal posterior distribution of some selected parameters. We apply this test to state of the art cosmological data sets, to assess their agreement within the $\Lambda$CDM model. We find that there is a good level of concordance between all the experiments with one noticeable exception. There is substantial evidence of tension between the CMB, temperature and polarization, measurements of the Planck satellite and the data from the CFHTLenS weak lensing survey even when applying ultra conservative cuts. These results robustly point toward the possibility of having unaccounted systematic effects in the data, an incomplete modelling of the cosmological predictions or hints toward new physical phenomena.