{"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/two-meson-form-factors-in-unitarized-chiral","title":"Two-Meson Form Factors in Unitarized Chiral Perturbation Theory","arxiv_id":"2011.00921","date":"2020-11-02","proceeding":null,"authors":["Yu-Ji Shi","Chien-Yeah Seng","Feng-Kun Guo","Bastian Kubis","Ulf-G. Meißner","Wei Wang"],"abstract":"We present a comprehensive analysis of form factors for two light pseudoscalar mesons induced by scalar, vector, and tensor quark operators. The theoretical framework is based on a combination of unitarized chiral perturbation theory and dispersion relations. The low-energy constants in chiral perturbation theory are fixed by a global fit to the available data of the two-meson scattering phase shifts. Each form factor derived from unitarized chiral perturbation theory is improved by iteratively applying a dispersion relation. This study updates the existing results in the literature and explores those that have not been systematically studied previously, in particular the two-meson tensor form factors within unitarized chiral perturbation theory. We also discuss the applications of these form factors as mandatory inputs for low-energy phenomena, such as the semi-leptonic decays $B_s\\to \\pi^+\\pi^-\\ell^+\\ell^-$ and the $\\tau$ lepton decay $\\tau\\rightarrow\\pi^{-}\\pi^{0}\\nu_{\\tau}$, in searches for physics beyond the Standard Model.","url_abs":"https://arxiv.org/abs/2011.00921v2","url_pdf":"https://arxiv.org/pdf/2011.00921v2.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":"two-meson-form-factors-in-unitarized-chiral","repo_url":"https://github.com/fkguo/IAMfit","is_official":0,"mentioned_in_paper":0,"mentioned_in_github":1,"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}