Improved Standard-Model prediction for K L → ℓ + ℓ −
Abstract We present a comprehensive calculation of the K L → γ ∗ γ ∗ form factor in dispersion theory, using input from the leptonic decays K L → ℓ + ℓ − γ, $${K}_{L}\to {{\ell}}_{1}^{+}{{\ell}}_{1}^{-}{{\ell}}_{2}^{+}{{\ell}}_{2}^{-}$$ , the hadronic mode K L → π + π − γ, the normalization K L → γγ...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2024-04-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP04(2024)071 |
| _version_ | 1827176250982006784 |
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| author | Martin Hoferichter Bai-Long Hoid Jacobo Ruiz de Elvira |
| author_facet | Martin Hoferichter Bai-Long Hoid Jacobo Ruiz de Elvira |
| author_sort | Martin Hoferichter |
| collection | DOAJ |
| description | Abstract We present a comprehensive calculation of the K L → γ ∗ γ ∗ form factor in dispersion theory, using input from the leptonic decays K L → ℓ + ℓ − γ, $${K}_{L}\to {{\ell}}_{1}^{+}{{\ell}}_{1}^{-}{{\ell}}_{2}^{+}{{\ell}}_{2}^{-}$$ , the hadronic mode K L → π + π − γ, the normalization K L → γγ, and the matching to asymptotic constraints. As key result we obtain an improved determination of the long-distance contribution to K L → ℓ + ℓ − , leading to the Standard-Model predictions Br[K L → μ + μ − ] = $${7.44}_{-0.34}^{+0.41}$$ × 10 −9, Br[K L → e + e − ] = 8.46(37) × 10 −12, and more stringent limits on physics beyond the Standard Model. We provide a detailed breakdown of the current uncertainty, and delineate how future experiments and the interplay with lattice QCD could help further improve the precision. |
| first_indexed | 2024-04-24T09:56:59Z |
| format | Article |
| id | doaj.art-c252f6cac4134086b7c8fd3a13c01a49 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2025-03-21T04:24:22Z |
| publishDate | 2024-04-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-c252f6cac4134086b7c8fd3a13c01a492024-07-28T11:05:59ZengSpringerOpenJournal of High Energy Physics1029-84792024-04-012024414010.1007/JHEP04(2024)071Improved Standard-Model prediction for K L → ℓ + ℓ −Martin Hoferichter0Bai-Long Hoid1Jacobo Ruiz de Elvira2Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of BernAlbert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of BernDepartamento de Física Teórica and IPARCOS, Facultad de Ciencias Físicas, Universidad Complutense de MadridAbstract We present a comprehensive calculation of the K L → γ ∗ γ ∗ form factor in dispersion theory, using input from the leptonic decays K L → ℓ + ℓ − γ, $${K}_{L}\to {{\ell}}_{1}^{+}{{\ell}}_{1}^{-}{{\ell}}_{2}^{+}{{\ell}}_{2}^{-}$$ , the hadronic mode K L → π + π − γ, the normalization K L → γγ, and the matching to asymptotic constraints. As key result we obtain an improved determination of the long-distance contribution to K L → ℓ + ℓ − , leading to the Standard-Model predictions Br[K L → μ + μ − ] = $${7.44}_{-0.34}^{+0.41}$$ × 10 −9, Br[K L → e + e − ] = 8.46(37) × 10 −12, and more stringent limits on physics beyond the Standard Model. We provide a detailed breakdown of the current uncertainty, and delineate how future experiments and the interplay with lattice QCD could help further improve the precision.https://doi.org/10.1007/JHEP04(2024)071KaonsRare Decays |
| spellingShingle | Martin Hoferichter Bai-Long Hoid Jacobo Ruiz de Elvira Improved Standard-Model prediction for K L → ℓ + ℓ − Journal of High Energy Physics Kaons Rare Decays |
| title | Improved Standard-Model prediction for K L → ℓ + ℓ − |
| title_full | Improved Standard-Model prediction for K L → ℓ + ℓ − |
| title_fullStr | Improved Standard-Model prediction for K L → ℓ + ℓ − |
| title_full_unstemmed | Improved Standard-Model prediction for K L → ℓ + ℓ − |
| title_short | Improved Standard-Model prediction for K L → ℓ + ℓ − |
| title_sort | improved standard model prediction for k l l l |
| topic | Kaons Rare Decays |
| url | https://doi.org/10.1007/JHEP04(2024)071 |
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