Dispersion relation for hadronic light-by-light scattering: pion pole
Abstract The pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon (g − 2) μ is fully determined by the doubly-virtual pion transition form factor. Although this crucial input quantity is, in principle, directly accessible in experiment, a complete...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2018-10-01
|
| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1007/JHEP10(2018)141 |
| _version_ | 1818173084140568576 |
|---|---|
| author | Martin Hoferichter Bai-Long Hoid Bastian Kubis Stefan Leupold Sebastian P. Schneider |
| author_facet | Martin Hoferichter Bai-Long Hoid Bastian Kubis Stefan Leupold Sebastian P. Schneider |
| author_sort | Martin Hoferichter |
| collection | DOAJ |
| description | Abstract The pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon (g − 2) μ is fully determined by the doubly-virtual pion transition form factor. Although this crucial input quantity is, in principle, directly accessible in experiment, a complete measurement covering all kinematic regions relevant for (g −2) μ is not realistic in the foreseeable future. Here, we report in detail on a reconstruction from available data, both space- and time-like, using a dispersive representation that accounts for all the low-lying singularities, reproduces the correct high- and low-energy limits, and proves convenient for the evaluation of the (g − 2) μ loop integral. We concentrate on the systematics of the fit to e + e − → 3π data, which are key in constraining the isoscalar dependence, as well as the matching to the asymptotic limits. In particular, we provide a detailed account of the pion transition form factor at low energies in the time- and space-like region, including the error estimates underlying our final result for the pion-pole contribution, a μ π 0 − pole = 62.6 − 2.5 + 3.0 × 10 − 11 $$ {a}_{\mu}^{\uppi^0-\mathrm{pole}}={62.6}_{-2.5}^{+3.0}\times {10}^{-11} $$ , and demonstrate how forthcoming singly-virtual measurements will further reduce its uncertainty. |
| first_indexed | 2024-12-11T19:22:53Z |
| format | Article |
| id | doaj.art-1aee0ab73a824870baa4fb62ff8fd1da |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-12-11T19:22:53Z |
| publishDate | 2018-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-1aee0ab73a824870baa4fb62ff8fd1da2022-12-22T00:53:28ZengSpringerOpenJournal of High Energy Physics1029-84792018-10-0120181015710.1007/JHEP10(2018)141Dispersion relation for hadronic light-by-light scattering: pion poleMartin Hoferichter0Bai-Long Hoid1Bastian Kubis2Stefan Leupold3Sebastian P. Schneider4Institute for Nuclear Theory, University of WashingtonHelmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität BonnHelmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität BonnInstitutionen för fysik och astronomi, Uppsala UniversitetHelmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität BonnAbstract The pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon (g − 2) μ is fully determined by the doubly-virtual pion transition form factor. Although this crucial input quantity is, in principle, directly accessible in experiment, a complete measurement covering all kinematic regions relevant for (g −2) μ is not realistic in the foreseeable future. Here, we report in detail on a reconstruction from available data, both space- and time-like, using a dispersive representation that accounts for all the low-lying singularities, reproduces the correct high- and low-energy limits, and proves convenient for the evaluation of the (g − 2) μ loop integral. We concentrate on the systematics of the fit to e + e − → 3π data, which are key in constraining the isoscalar dependence, as well as the matching to the asymptotic limits. In particular, we provide a detailed account of the pion transition form factor at low energies in the time- and space-like region, including the error estimates underlying our final result for the pion-pole contribution, a μ π 0 − pole = 62.6 − 2.5 + 3.0 × 10 − 11 $$ {a}_{\mu}^{\uppi^0-\mathrm{pole}}={62.6}_{-2.5}^{+3.0}\times {10}^{-11} $$ , and demonstrate how forthcoming singly-virtual measurements will further reduce its uncertainty.http://link.springer.com/article/10.1007/JHEP10(2018)141Chiral LagrangiansEffective Field TheoriesNonperturbative EffectsPrecision QED |
| spellingShingle | Martin Hoferichter Bai-Long Hoid Bastian Kubis Stefan Leupold Sebastian P. Schneider Dispersion relation for hadronic light-by-light scattering: pion pole Journal of High Energy Physics Chiral Lagrangians Effective Field Theories Nonperturbative Effects Precision QED |
| title | Dispersion relation for hadronic light-by-light scattering: pion pole |
| title_full | Dispersion relation for hadronic light-by-light scattering: pion pole |
| title_fullStr | Dispersion relation for hadronic light-by-light scattering: pion pole |
| title_full_unstemmed | Dispersion relation for hadronic light-by-light scattering: pion pole |
| title_short | Dispersion relation for hadronic light-by-light scattering: pion pole |
| title_sort | dispersion relation for hadronic light by light scattering pion pole |
| topic | Chiral Lagrangians Effective Field Theories Nonperturbative Effects Precision QED |
| url | http://link.springer.com/article/10.1007/JHEP10(2018)141 |
| work_keys_str_mv | AT martinhoferichter dispersionrelationforhadroniclightbylightscatteringpionpole AT bailonghoid dispersionrelationforhadroniclightbylightscatteringpionpole AT bastiankubis dispersionrelationforhadroniclightbylightscatteringpionpole AT stefanleupold dispersionrelationforhadroniclightbylightscatteringpionpole AT sebastianpschneider dispersionrelationforhadroniclightbylightscatteringpionpole |