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, AL. Considering Planck spectra alone, we find statistically significant evidence for scale dependence (`running') of AL. We then demonstrate that the anomaly is entirely driven by Planck's low multipoles, ℓ ≤ 30. When these data points are excluded, a joint analysis with several other datasets clearly favors ΛCDM over the extended ΛCDM + AL model. Not only that the lensing anomaly and low ℓ anomaly of the CMB go away in this case, but also the S8 tension is ameliorated, and only the Hubble tension persists.