CMB circular and B-mode polarization from new interactions
Abstract
Standard models describing the radiation transfer of the cosmic microwave background (CMB) through Compton scattering predict that cosmological scalar perturbations at linear order are not able to source V and B polarization modes. In this work, we investigate the possibility that such CMB polarization modes are generated even in the presence of linear scalar perturbations only. We provide a general parametrization of the photon-fermion forward-scattering amplitude and compute mixing terms between different CMB polarization modes. We discuss different general extensions of Standard Model interactions which violate discrete symmetries, while preserving the combination of charge conjugation, parity and time reversal. We show that it is possible to source CMB circular polarization by violating parity and charge conjugation symmetries. Instead, B-mode generation is associated to the violation of symmetry for time-reversal. Our results provide a useful tool to constrain new physics using CMB data.
Cite
@article{arxiv.1903.04578,
title = {CMB circular and B-mode polarization from new interactions},
author = {Nicola Bartolo and Ahmad Hoseinpour and Sabino Matarrese and Giorgio Orlando and Moslem Zarei},
journal= {arXiv preprint arXiv:1903.04578},
year = {2019}
}
Comments
22 pages, 2 figures; v2: Appendix added. Some assumptions have been relaxed without significant modifications in the final results. Replaced to match published version in PRD