Virtual Compton Scattering and the Generalized Polarizabilities of the Proton at Q^2=0.92 and 1.76 GeV^2

TL;DR

This study measures the electric and magnetic generalized polarizabilities of the proton at specific momentum transfers using virtual Compton scattering, revealing their complex behavior across a range of Q^2 values.

Contribution

It provides new experimental data on proton GPs at higher Q^2, extending the understanding of proton structure beyond previous measurements.

Findings

Determined proton structure functions P_LL-P_TT/epsilon and P_LT.

Measured electric and magnetic GPs at Q^2=0.92 and 1.76 GeV^2.

Revealed non-trivial Q^2 dependence of proton GPs.

Abstract

Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson Lab using the exclusive photon electroproduction reaction (e p --> e p gamma). This paper gives a detailed account of the analysis which has led to the determination of the structure functions P_LL-P_TT/epsilon and P_LT, and the electric and magnetic generalized polarizabilities (GPs) alpha_E(Q^2) and beta_M(Q^2) at values of the four-momentum transfer squared Q^2= 0.92 and 1.76 GeV^2. These data, together with the results of VCS experiments at lower momenta, help building a coherent picture of the electric and magnetic GPs of the proton over the full measured Q^2-range, and point to their non-trivial behavior.