CMB lensing in a modified $\Lambda$CDM model in light of the $H_0$ tension

TL;DR

This paper investigates a modified DM model, called "uDM, which aims to resolve the H_0 tension and related CMB observations discrepancies by analyzing its predictions for CMB lensing and temperature power spectra.

Contribution

The study introduces the "uDM model as a new approach that simultaneously alleviates the H_0 tension and CMB data inconsistencies, with a comparable number of parameters to DM.

Findings

"uDM relaxes TT spectrum inconsistencies.

It reduces CMB lensing tensions.

Provides a better fit with hi^2 improvement of -3.3.

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 $\Delta \chi^2=-3.3$.