Determining the Meson Cloud Contribution of Nucleon Electromagnetic Form Factor Using Dispersion Relation

TL;DR

This paper investigates the meson cloud's role in nucleon electromagnetic form factors using dispersion relations, combining experimental pion-nucleon scattering data with quark model calculations to accurately reproduce proton charge radius.

Contribution

It introduces a method that integrates experimental scattering data with quark core models to analyze meson cloud effects on nucleon form factors.

Findings

Proton electromagnetic form factors are well reproduced.

Proton charge radius matches experimental data.

Quark core radius is consistent with expectations.

Abstract

We explore the meson cloud contribution to nucleon electromagnetic form factors in dispersion relation approach. In our calculations, experimental data on transition amplitudes for pion-nucleon scatterings are taken directly as inputs, with the assumption that the photon-pion interaction dominates over other meson-photon couplings. Combining with the quark core contribution evaluated in quark model, the proton electromagnetic form factors are well reproduced in the work. The resulting mean-square charge radius of the proton agrees well with experimental data, and the quark core radius is reasonable.