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arXiv · 2208.08101

Can primordial parity violation explain the observed cosmic birefringence?

Tomohiro Fujita·Yuto Minami·Maresuke Shiraishi·Shuichiro Yokoyama
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Abstract

Recently, the cross-correlation between $E$- and $B$-mode polarization of the cosmic microwave background (CMB), which is well explained by cosmic birefringence with rotation angle $\beta\approx 0.3$ deg, has been found in CMB polarization data. We carefully investigate the possibility of explaining the observed $EB$ correlation by the primordial chiral gravitational waves (CGWs), which can be generated in the parity-violating theories in the primordial Universe. We found that the CGWs scenario does not work due to the overproduction of the $BB$ auto-correlation which far exceeds the observed one by SPTPol and POLARBEAR.

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Tomohiro Fujita, Yuto Minami, Maresuke Shiraishi, Shuichiro Yokoyama. 2022-08-17. Can primordial parity violation explain the observed cosmic birefringence?. https://doi.org/10.1103/physrevd.106.103529

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