The proton radius and its relatives -- much ado about nothing?

TL;DR

This paper reviews the dispersion-theoretical analysis of nucleon electromagnetic form factors, focusing on extracting the proton charge radius and related quantities, and discusses recent developments in hyperfine splitting and radiative corrections.

Contribution

It provides a comprehensive summary of dispersion-theoretical methods for nucleon form factors and discusses recent advances in related experimental and theoretical studies.

Findings

Extraction of proton charge radius using dispersion analysis

Discussion of recent hyperfine splitting measurements

Analysis of radiative corrections to muon-proton scattering

Abstract

I summarize the dispersion-theoretical analysis of the nucleon electromagnetic form factors. Special emphasis is given on the extraction of the proton charge radius and its relatives, the proton magnetic radius as well as the neutron magnetic radius. Some recent work on the hyperfine splitting in leptonic hydrogen and on radiative corrections to muon-proton scattering is also discussed. Some views on future studies are given.