Impact of Low ell's on Large Scale Structure Anomalies

Abstract

We scrutinize the reported lensing anomaly of the CMB by considering several phenomenological modifications of the lensing consistency parameter, $A_{\mathrm{L}}$. Considering Planck spectra alone, we find statisically significant evidence for scale dependence (`running') of $A_{\mathrm{L}}$. We then demonstrate that the anomaly is entirely driven by Planck's low multipoles, $\ell \le 30$. When these data points are excluded a joint analysis with several other datasets clearly favors $\Lambda$CDM over the extended $\Lambda \mathrm{CDM}+{\mathrm{A}}_{\mathrm{L}}$ model. Not only that the lensing anomaly and low $\ell$ anomaly of the CMB go away in this case, but also the $S_8$ tension is ameliorated, and only the Hubble tension persists.

Comments: 33 pages, 9 figures, and 8 tables. 2409.15457