This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process epe'pπ+π . The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2 < Q2 < 0.6 GeV2 and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q2 covered by the measurements. A phenomenological analysis of the data allowed us to establish the most significant mechanisms contributing to the reaction. The nonresonant mechanisms account for a major part of cross sections. However, we find sensitivity to s-channel excitations of low-mass nucleon resonances, especially to the N(1440)P11 and N(1520)D13 states in kinematic dependencies of the one-fold differential cross sections.

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Copyright © 2009 American Physical Society. This article first appeared in Physical Review C 79, no. 1 (January 20, 2009): 015204-1-15204-23. doi:10.1103/PhysRevC.79.015204.

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