Recent Results on Proton Charge Radius and Polarizabilities

Abstract

The proton charge radius and nucleon electromagnetic polarizabilities are fundamental properties probing the electromagnetic structure of the nucleons. Proton charge radius is directly related to the proton charge distribution and the nucleon electromagnetic polarizabilities characterize the response of the charge/magnetic constituents inside the nucleon to external electromagnetic fields. A precise understanding of these quantities is crucial not only for understanding how Quantum Chromodynamics (QCD) works in the non-perturbative QCD region but also for bound state Quantum Electrodynamics (QED) calculations of atomic energy levels. We discuss the experimental approaches employed in the recent decades to determine the proton charge radius and nucleon electromagnetic polarizabilities. We summarize the present status of the proton charge radius puzzle and polarizabilities measurements. Additionally, we provide prospects for various upcoming experiments.