Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models
Abstract While the low-energy part of the hadronic light-by-light (HLbL) tensor can be constrained from data using dispersion relations, for a full evaluation of its contribution to the anomalous magnetic moment of the muon (g − 2) μ also mixed- and high-energy regions need to be estimated. Both can...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-03-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | http://link.springer.com/article/10.1007/JHEP03(2020)101 |
| _version_ | 1818533905205035008 |
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| author | Gilberto Colangelo Franziska Hagelstein Martin Hoferichter Laetitia Laub Peter Stoffer |
| author_facet | Gilberto Colangelo Franziska Hagelstein Martin Hoferichter Laetitia Laub Peter Stoffer |
| author_sort | Gilberto Colangelo |
| collection | DOAJ |
| description | Abstract While the low-energy part of the hadronic light-by-light (HLbL) tensor can be constrained from data using dispersion relations, for a full evaluation of its contribution to the anomalous magnetic moment of the muon (g − 2) μ also mixed- and high-energy regions need to be estimated. Both can be addressed within the operator product expansion (OPE), either for configurations where all photon virtualities become large or one of them remains finite. Imposing such short-distance constraints (SDCs) on the HLbL tensor is thus a major aspect of a model-independent approach towards HLbL scattering. Here, we focus on longitudinal SDCs, which concern the amplitudes containing the pseudoscalar-pole contributions from π 0, η, η′. Since these conditions cannot be fulfilled by a finite number of pseudoscalar poles, we consider a tower of excited pseudoscalars, constraining their masses and transition form factors from Regge theory, the OPE, and phenomenology. Implementing a matching of the resulting expressions for the HLbL tensor onto the perturbative QCD quark loop, we are able to further constrain our calculation and significantly reduce its model dependence. We find that especially for the π 0 the corresponding increase of the HLbL contribution is much smaller than previous prescriptions in the literature would imply. Overall, we estimate that longitudinal SDCs increase the HLbL contribution by Δ a μ LSDC = 13 6 $$ \varDelta {a}_{\mu}^{\mathrm{LSDC}}=13(6) $$ × 10-11. This number does not include the contribution from the charm quark, for which we find a μ c − quark $$ {a}_{\mu}^{c- quark} $$ = 3(1) × 10 −11. |
| first_indexed | 2024-12-11T18:04:53Z |
| format | Article |
| id | doaj.art-91a79de1972242e7a92bfed537826436 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-12-11T18:04:53Z |
| publishDate | 2020-03-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-91a79de1972242e7a92bfed5378264362022-12-22T00:55:46ZengSpringerOpenJournal of High Energy Physics1029-84792020-03-012020318910.1007/JHEP03(2020)101Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge modelsGilberto Colangelo0Franziska Hagelstein1Martin Hoferichter2Laetitia Laub3Peter Stoffer4Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of BernAlbert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of BernAlbert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of BernAlbert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of BernDepartment of Physics, University of California at San DiegoAbstract While the low-energy part of the hadronic light-by-light (HLbL) tensor can be constrained from data using dispersion relations, for a full evaluation of its contribution to the anomalous magnetic moment of the muon (g − 2) μ also mixed- and high-energy regions need to be estimated. Both can be addressed within the operator product expansion (OPE), either for configurations where all photon virtualities become large or one of them remains finite. Imposing such short-distance constraints (SDCs) on the HLbL tensor is thus a major aspect of a model-independent approach towards HLbL scattering. Here, we focus on longitudinal SDCs, which concern the amplitudes containing the pseudoscalar-pole contributions from π 0, η, η′. Since these conditions cannot be fulfilled by a finite number of pseudoscalar poles, we consider a tower of excited pseudoscalars, constraining their masses and transition form factors from Regge theory, the OPE, and phenomenology. Implementing a matching of the resulting expressions for the HLbL tensor onto the perturbative QCD quark loop, we are able to further constrain our calculation and significantly reduce its model dependence. We find that especially for the π 0 the corresponding increase of the HLbL contribution is much smaller than previous prescriptions in the literature would imply. Overall, we estimate that longitudinal SDCs increase the HLbL contribution by Δ a μ LSDC = 13 6 $$ \varDelta {a}_{\mu}^{\mathrm{LSDC}}=13(6) $$ × 10-11. This number does not include the contribution from the charm quark, for which we find a μ c − quark $$ {a}_{\mu}^{c- quark} $$ = 3(1) × 10 −11.http://link.springer.com/article/10.1007/JHEP03(2020)101Chiral LagrangiansEffective Field TheoriesNonperturbative EffectsPrecision QED |
| spellingShingle | Gilberto Colangelo Franziska Hagelstein Martin Hoferichter Laetitia Laub Peter Stoffer Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models Journal of High Energy Physics Chiral Lagrangians Effective Field Theories Nonperturbative Effects Precision QED |
| title | Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models |
| title_full | Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models |
| title_fullStr | Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models |
| title_full_unstemmed | Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models |
| title_short | Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2) μ with large-N c Regge models |
| title_sort | longitudinal short distance constraints for the hadronic light by light contribution to g 2 μ with large n c regge models |
| topic | Chiral Lagrangians Effective Field Theories Nonperturbative Effects Precision QED |
| url | http://link.springer.com/article/10.1007/JHEP03(2020)101 |
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