Virtual compton scattering at Jefferson Laboratory

Virtual Compton Scattering (VCS) off the proton below pion production threshold allows to measure at fixed four-momentum squared 6 new observables of the proton called the Generalized Polarizabilities. Their determination will put new constraints on models of nucleon structure. Experimentally, we measure an absolute cross section of photon electro-production off the proton (ep → ep γ). At Jefferson Laboratory (Virginia, USA), the scattered electron is detected in coincidence with the recoiling proton in two high resolution spectrometers in order to access the missing particle.