Nucleon Form Factors in the Space- and Timelike Regions

TL;DR

This paper reviews dispersion relation methods for nucleon electromagnetic form factors, highlighting recent analyses in both spacelike and timelike regions, including low-momentum transfer results from chiral perturbation theory.

Contribution

It provides an overview of dispersion theory applications to nucleon form factors and presents recent analysis results, emphasizing the timelike region and low-momentum transfer insights.

Findings

Dispersion relations effectively describe nucleon form factors in both regions.

Recent analysis offers new constraints on timelike form factors.

ChPT results contribute to understanding low-momentum transfer behavior.

Abstract

Dispersion relations provide a powerful tool to describe the electromagnetic form factors of the nucleon both in the spacelike and timelike regions with constraints from unitarity and perturbative QCD. We give a brief introduction into dispersion theory for nucleon form factors and present results from a recent form factor analysis. Particular emphasis is given to the form factors in the timelike region. Furthermore, some recent results for the spacelike form factors at low momentum transfer from a ChPT calculation by Kubis and Meissner are discussed.