Document Type


Publication Date




Publication Title

Physical Review C






045206 (1-19)


We report measurements of target- and double-spin asymmetries for the exclusive channel ep → 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.


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Original Publication Citation

CLAS Collaboration, Zheng, X., Adhikari, K. P., Bosted, P., Deur, A., Drozdov, V., . . . Zonta, I. (2016). Measurement of target and double-spin asymmetries for the ep → eπ+(n) reaction in the nucleon resonance region at low Q². Physical Review C, 94(4), 045206. doi:10.1103/PhysRevC.94.045206


0000-0003-2243-6836 (Kuhn), 0000-0003-1582-2376 (Dodge), 0000-0001-5416-2900 (Weinstein)

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