Internal delensing of Cosmic Microwave Background polarization B-modes with the POLARBEAR experiment

TL;DR

This paper demonstrates a significant internal delensing of CMB B-modes using POLARBEAR data, reducing B-mode power variance and enhancing constraints on inflationary models for future experiments.

Contribution

It introduces an iterative maximum a posteriori delensing method and achieves the highest internal delensing efficiency to date with POLARBEAR data.

Findings

14% reduction in B-mode power variance

Achieved >5σ significance in delensing measurement

Demonstrated potential for improved inflationary constraints

Abstract

Using only cosmic microwave background polarization data from the POLARBEAR experiment, we measure $B$-mode polarization delensing on subdegree scales at more than $5\sigma$ significance. We achieve a 14% $B$-mode power variance reduction, the highest to date for internal delensing, and improve this result to 2% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial $B$-mode experiments.