Model Analysis of the $ep \to ep'\pi^+\pi^-$ Electroproduction Reaction   on the Proton
  Recent CLAS data on the $p\pi^+\pi^-$ electroproduction off protons at 1.3$<$W$<$1.57 GeV and 0.25$<$$Q^{2}$$<$0.6 GeV$^{2}$ have been analyzed using a meson-baryon phenomenological model. By fitting nine 1-fold differential cross section data for each $W$ and $Q^{2}$ bin, the charged double pion electroproduction mechanisms are identified from their manifestations in the observables. We have extracted the cross sections from amplitudes of each of the considered isobar channels as well as from their coherent sum. We also obtained non-resonant partial wave amplitudes of all contributing isobar channels which could be useful for advancing a complete coupled-channel analysis of all meson electroproduction data. 
Viktor Mokeev, Volker Burkert, Tsung-Shung H. Lee, Latifa Elouadrhiri,   Gleb Fedotov, Boris Ishkhanov