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Title: Dispersion relation for hadronic light-by-light scattering: pion pole

Abstract

Here, 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 π0–pole μ = 62.6 +3.0 –2.5 × 10 –11, and demonstrate how forthcoming singly-virtual measurements will further reduce its uncertainty.

Authors:
ORCiD logo [1];  [2];  [2];  [3];  [2]
  1. Univ. of Washington, Seattle, WA (United States)
  2. Univ. Bonn, Bonn (Germany)
  3. Uppsala Univ., Uppsala (Sweden)
Publication Date:
Research Org.:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1483939
Grant/Contract Number:  
FG02-00ER41132
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Volume: 2018; Journal Issue: 10; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Chiral Lagrangians; Effective Field Theories; Nonperturbative Effects; Precision QED

Citation Formats

Hoferichter, Martin, Hoid, Bai -Long, Kubis, Bastian, Leupold, Stefan, and Schneider, Sebastian P. Dispersion relation for hadronic light-by-light scattering: pion pole. United States: N. p., 2018. Web. doi:10.1007/JHEP10(2018)141.
Hoferichter, Martin, Hoid, Bai -Long, Kubis, Bastian, Leupold, Stefan, & Schneider, Sebastian P. Dispersion relation for hadronic light-by-light scattering: pion pole. United States. doi:10.1007/JHEP10(2018)141.
Hoferichter, Martin, Hoid, Bai -Long, Kubis, Bastian, Leupold, Stefan, and Schneider, Sebastian P. Tue . "Dispersion relation for hadronic light-by-light scattering: pion pole". United States. doi:10.1007/JHEP10(2018)141. https://www.osti.gov/servlets/purl/1483939.
@article{osti_1483939,
title = {Dispersion relation for hadronic light-by-light scattering: pion pole},
author = {Hoferichter, Martin and Hoid, Bai -Long and Kubis, Bastian and Leupold, Stefan and Schneider, Sebastian P.},
abstractNote = {Here, 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, aπ0–poleμ = 62.6+3.0–2.5 × 10–11, and demonstrate how forthcoming singly-virtual measurements will further reduce its uncertainty.},
doi = {10.1007/JHEP10(2018)141},
journal = {Journal of High Energy Physics (Online)},
issn = {1029-8479},
number = 10,
volume = 2018,
place = {United States},
year = {2018},
month = {10}
}

Journal Article:
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