{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/improved-constraints-on-cosmic-birefringence","title":"Improved Constraints on Cosmic Birefringence from the WMAP and Planck Cosmic Microwave Background Polarization Data","arxiv_id":"2205.13962","date":"2022-05-27","proceeding":null,"authors":["Johannes R. Eskilt","Eiichiro Komatsu"],"abstract":"The observed pattern of linear polarization of the cosmic microwave background (CMB) photons is a sensitive probe of physics violating parity symmetry under inversion of spatial coordinates. A new parity-violating interaction might have rotated the plane of linear polarization by an angle $\\beta$ as the CMB photons have been traveling for more than 13 billion years. This effect is known as \"cosmic birefringence.\" In this paper, we present new measurements of cosmic birefringence from a joint analysis of polarization data from two space missions, Planck and WMAP. This dataset covers a wide range of frequencies from 23 to 353 GHz. We measure $\\beta = 0.342^{\\circ\\,+0.094^\\circ}_{\\phantom{\\circ\\,}-0.091^\\circ}$ (68% C.L.) for nearly full-sky data, which excludes $\\beta=0$ at 99.987% C.L. This corresponds to the statistical significance of $3.6\\sigma$. There is no evidence for frequency dependence of $\\beta$. We find a similar result, albeit with a larger uncertainty, when removing the Galactic plane from the analysis.","url_abs":"https://arxiv.org/abs/2205.13962v2","url_pdf":"https://arxiv.org/pdf/2205.13962v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"improved-constraints-on-cosmic-birefringence","repo_url":"https://github.com/LilleJohs/Cosmic_Birefringence","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}