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We report measurements of target- and double-spin asymmetries for the exclusive channel ⃗e⃗p→eπ+(n) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35(GeV/c)2. The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6∘. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.
Available at: http://works.bepress.com/angela_biselli/104/
Copyright 2016 American Physical Society
Archived here with permission from the copyright holder.
Original publication available here: https://journals.aps.org/prc/abstract/10.1103/PhysRevC.94.045206