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| Autores principales: | , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| Acceso en línea: | https://arxiv.org/abs/2510.25489 |
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| _version_ | 1866912708595548160 |
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| author | Yin, Lu Xiong, Shuhang Kochappan, Joby Lee, Bum-Hoon Ghosh, Tuhin |
| author_facet | Yin, Lu Xiong, Shuhang Kochappan, Joby Lee, Bum-Hoon Ghosh, Tuhin |
| contents | The Early Dark Energy (EDE) model has been proposed as a candidate mechanism to generate cosmic birefringence through a Chern-Simons coupling between a dynamical scalar field and the cosmic microwave background (CMB) photon. Such birefringence induces a nonzero cross-correlation between the CMB $E$- and $B$-modes, providing a direct observational signature of parity violation. Recent measurements of the $EB$ and $TB$ power spectra, however, cannot yet unambiguously separate instrumental miscalibration ($α$) from a true cosmic-rotation angle ($β$). For this reason, we perform a model-independent analysis in terms of the total effective rotation angle $α+β$. We analyze the latest $EB$ and $TB$ measurements from the SPIDER, Planck, and ACT experiments and derive constraints on the Chern-Simons coupling constant $gM_{Pl}$ and on the polarization rotation angle $α+β$. We find that the coupling $gM_{Pl}$ is not compatible with the SPIDER data, while it provides reasonable fits to the Planck and ACT measurements. The fits for $α+β$ prefer a value larger than zero: when combined, Planck+ACT yield a detection significance of approximately 7$σ$. We also find that ACT data alone do not provide sufficiently tight constraints on either $gM_{Pl}$ or $α+β$, whereas the combination Planck+ACT improves the statistical consistency of ACT's high-$\ell$ results and leads to a better PTE for those measurements. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_25489 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Constraints on Cosmic Birefringence from SPIDER, Planck, and ACT observations Yin, Lu Xiong, Shuhang Kochappan, Joby Lee, Bum-Hoon Ghosh, Tuhin Cosmology and Nongalactic Astrophysics The Early Dark Energy (EDE) model has been proposed as a candidate mechanism to generate cosmic birefringence through a Chern-Simons coupling between a dynamical scalar field and the cosmic microwave background (CMB) photon. Such birefringence induces a nonzero cross-correlation between the CMB $E$- and $B$-modes, providing a direct observational signature of parity violation. Recent measurements of the $EB$ and $TB$ power spectra, however, cannot yet unambiguously separate instrumental miscalibration ($α$) from a true cosmic-rotation angle ($β$). For this reason, we perform a model-independent analysis in terms of the total effective rotation angle $α+β$. We analyze the latest $EB$ and $TB$ measurements from the SPIDER, Planck, and ACT experiments and derive constraints on the Chern-Simons coupling constant $gM_{Pl}$ and on the polarization rotation angle $α+β$. We find that the coupling $gM_{Pl}$ is not compatible with the SPIDER data, while it provides reasonable fits to the Planck and ACT measurements. The fits for $α+β$ prefer a value larger than zero: when combined, Planck+ACT yield a detection significance of approximately 7$σ$. We also find that ACT data alone do not provide sufficiently tight constraints on either $gM_{Pl}$ or $α+β$, whereas the combination Planck+ACT improves the statistical consistency of ACT's high-$\ell$ results and leads to a better PTE for those measurements. |
| title | Constraints on Cosmic Birefringence from SPIDER, Planck, and ACT observations |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2510.25489 |