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arXiv · 2602.23044

Form factors of the $\rho$ meson from effective field theory and the lattice

Ulf-G. Meißner·Akaki Rusetsky·Ajay S. Sakthivasan·Gerrit Schierholz·Jia-Jun Wu
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Abstract

The calculation of resonance form factors in effective field theory as well as on the lattice is a highly challenging task. In a recent paper, we proposed a novel method based on the introduction of a background field and the Feynman-Hellmann theorem to address the problem, and applied it to a toy model. In the present work we use this method for the electromagnetic form factors of the $\rho$-meson. By matching the results to Chiral Perturbation Theory, we provide a first, crude estimate of all three form factors of the $\rho$-meson within the effective field theory. Contact contributions to these form factors turn out to be substantial. A procedure for lattice calculations is outlined, paving the way for an ab initio approach to the problem.

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Ulf-G. Meißner, Akaki Rusetsky, Ajay S. Sakthivasan, Gerrit Schierholz, Jia-Jun Wu. 2026-02-26. Form factors of the $\rho$ meson from effective field theory and the lattice. https://doi.org/10.1007/jhep06(2026)164

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