Characterization of nuclear sources from neutron-neutron, proton-proton and neutron-proton correlation functions

We have extended a model for the gammaN ->pi piN reaction to virtual photons and selected the diagrams which have a A in the final state. With this model we have evaluated cross sections for the virtual photon cross section as a function of Q^2 for different energies. The agreement found with the gammavp -> delta^0 pi^+ T and gammavp -> delta^++pi^- reactions is good. The sensitivity of the results to N(delta) transition form factors is also studied. The present reaction, selecting a particular final state, is an extra test for models of the (gamma)vN -> pi pi N amplitude. The experimental measurement of the different isospin channels for this reaction are encouraged as a means to unravel the dynamics of the two pions photoproduction processes.