Free-form reconstruction of primordial power spectrum using Planck CMB temperature and polarization by Wuhyun Sohn et al. on Wednesday 30 November

We present a free-form reconstruction of the primordial power spectrum using

Planck 2018 CMB temperature and polarisation data. We extend the modified

Richardson-Lucy (MRL) algorithm to include polarisation and apply it to the

CamSpec unbinned $C_\ell$s. Combined with a new regularisation technique

inspired by the diffusion equation, we obtain a form of primordial power

spectrum with features that improve the fit to each of TT, TE, and EE data

simultaneously. The resulting features are consistent with the previous

findings from the temperature-only analyses. We evaluate the statistical

significance of the features in our reconstructions using simulated $C_\ell$s

and find the data to be consistent with having a featureless primordial power

spectrum. The machinery developed here will be a complimentary tool in the

search for features in the primordial power spectrum with upcoming CMB surveys.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15139v2