Quark Physics in Inelastic Virtual Compton Scattering

Abstract

Inelastic virtual Compton scattering of photons from nucleons for lepton-pair production, γ+p(n)→γ^*+anything and γ^*→l⁺+l⁻, is proposed to study not only the quark structure of the nucleon but that of the photon. In a special kinematical region, the cross section for this process measures the sum of quartic charges of quarks in the nucleon while in another region, it does the quark distribution function of the photon. The magnitude of the relevant cross section is estimated to be of order 10⁻³⁴ cm², which seems to be feasible for any future experiments by photon beams at energies higher than 1 GeV.