Virtual Compton scattering at low energies with a positron beam

TL;DR

This paper discusses the potential of using positron beams to study the electromagnetic structure of protons through low-energy virtual Compton scattering, complementing existing electron beam experiments.

Contribution

It presents an impact study of positron beam experiments for extracting generalized polarizabilities, offering a new approach to understanding proton structure.

Findings

Positron beams can provide complementary data to electron beams in VCS experiments.

A detailed impact study shows the potential benefits of positron experiments.

Further investigations are needed to unify GPs across energy scales.

Abstract

The Virtual Compton scattering (VCS) process at low energies explores the electromagnetic structure of the proton in terms of generalized polarizabilities (GPs). In the one-photon exchange approximation, VCS can be accessed with exclusive photon production reactions with electron or positron beams. The extraction of the GPs from VCS with electron beam has seen substantial progress over the past two decades. Nonetheless, a consistent picture of the GPs from low to higher scales demands further investigations. Complementary measurements with positron beams offer an unique possibility, and we present an impact study of such experimental program.