CMB lensing in a modified ΛCDM model in light of the H0 tension

Abstract

The observed discrepancy of the Hubble parameter measurements in the local universe with the cosmic microwave background (CMB) data may indicate a new physics. It is vital to test the alternative models that reconcile the Hubble tension with other cosmological observations in this direction. The CMB lensing is a crucial observation that relates the early universe perturbations to the matter's late-time distribution. In this work, we study the prediction of the \"u$\Lambda$CDM as a solution for $H_0$ tension for CMB lensing and the low- and high-$\ell$'s temperature (TT) power spectrum internal inconsistency. We show that this model relaxes the low- and high-$\ell$'s TT mild inconsistency and the CMB lensing tensions simultaneously. Accordingly, \"u$\Lambda$CDM having the same number of free parameters as $\Lambda$CDM with lensing amplitude $A_L$ added, has a better fit with $\Delta \chi^2=-3.3$.