Two-pion contributions to the muon g – 2

Stoffer, Peter; Colangelo, Gilberto; Hoferichter, Martin (28 February 2020). Two-pion contributions to the muon g – 2. PoS - proceedings of science, 317. Trieste, Italy: Scuola Internazionale Superiore di Studi Avanzati SISSA 10.22323/1.317.0084

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We perform a detailed analysis of e⁺e⁻− → π⁺π⁻ data for energies below 1GeV, based on a dispersive representation of the pion vector form factor. Using an extended Omnès representation and input for the ππ P-wave phase shift from a previous Roy-equation analysis, we express the pion vector form factor in terms of a few free parameters, which are fit to the modern high-statistics data sets. Statistically acceptable fits are obtained as soon as potential uncertainties in the energy calibration are taken into account. The fits prefer a mass of the ω meson significantly lower than the current PDG average. We perform a complete analysis of statistical and systematic uncertainties and derive the consequences for the two-pion contribution to hadronic vacuum polarization and the muon anomalous magnetic moment aμ. In a global fit, we find aμππ | ≤1 GeV μ ≤0.63 GeV = 495.0(1.5)(2.1) × 10⁻¹⁰ and aμππ | ≤0.63 GeV = 132.8(0.4)(1.0) × 10⁻¹⁰. As side products, we obtain improved constraints on the ππ P-wave as well as a determination of the pion charge radius, ⟨rπ²⟩ = 0.429(1)(4)fm².

Item Type:

Conference or Workshop Item (Paper)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Institute of Theoretical Physics

UniBE Contributor:

Colangelo, Gilberto and Hoferichter, Martin

Subjects:

500 Science > 530 Physics

ISSN:

1824-8039

Publisher:

Scuola Internazionale Superiore di Studi Avanzati SISSA

Language:

English

Submitter:

Esther Fiechter

Date Deposited:

15 Apr 2020 13:41

Last Modified:

15 Apr 2020 13:41

Publisher DOI:

10.22323/1.317.0084

BORIS DOI:

10.7892/boris.141396

URI:

https://boris.unibe.ch/id/eprint/141396

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