Cosmology with Planck T-E correlation coefficient

TL;DR

This paper introduces a new likelihood based on the Pearson correlation coefficient between temperature and polarization E modes in the CMB, providing constraints on cosmological parameters that are robust against certain instrumental systematics.

Contribution

It presents the first constraints on $ m extLambda$CDM parameters using the correlation coefficient, demonstrating its consistency with traditional power spectra analyses and robustness against multiplicative systematics.

Findings

Correlation coefficient constraints align with power spectra results.

Hubble parameter estimate is consistent with standard CMB analysis.

Correlation coefficient shows compatibility with ACTPol power spectra.

Abstract

Tensions in cosmological parameters measurement motivate a revisit of the effects of instrumental systematics. In this article, we focus on the Pearson's correlation coefficient of the cosmic microwave background temperature and polarization E modes $\mathcal{R}_\ell^{\rm TE}$ which has the property of not being biased by multiplicative instrumental systematics. We build a $\mathcal{R}_\ell^{\rm TE}$-based likelihood for the Planck data, and present the first constraints on $\Lambda$CDM parameters from the correlation coefficient. Our results are compatible with parameters derived from a power spectra based likelihood. In particular the value of the Hubble parameter $H_0$ characterizing the expansion of the Universe today, 67.5 $\pm$ 1.3 km/s/Mpc, is consistent with the ones inferred from standard CMB analysis. We also discuss the consistency of the Planck correlation coefficient with the one computed from the most recent ACTPol power spectra.