The exclusive electroproduction process e→p→e′nπ+ was measured in the range of the photon virtuality Q2=1.7-4.5 GeV2, and the invariant mass range for the nπ+ system of W=1.15-1.7 GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive π+ production from protons with nearly full coverage in the azimuthal and polar angles of the nπ+ center-of-mass system. The nπ+ channel has particular sensitivity to the isospin ½ excited nucleon states, and together with the pπ0 final state will serve to determine the transition form factors of a large number of resonances. The largest discrepancy between these results and present modes was seen in the σLT′ structure function. In this experiment, 31,295 cross section and 4,184 asymmetry data points were measured. Because of the large volume of data, only a reduced set of structure functions and Legendre polynomial moments can be presented that are obtained in model-independent fits to the differential cross sections.
Physical Review C
Park, K.; Biselli, Angela; and CLAS Collaboration, "Cross sections and beam asymmetries for e→p→enπ+ in the nucleon resonance region for 1.7" (2008). Physics Faculty Publications. 64.
K. Park et al. [CLAS Collaboration], "Cross sections and beam asymmetries for e→p→enπ+ in the nucleon resonance region for 1.7