Measurement of Target and Double-Spin Asymmetries for the ep → eπ+(n) Reaction in the Nucleon Resonance Region at Low Q²

Authors

CLAS Collaboration
K. P. Adhikari, Old Dominion University
S E. KuhnFollow
D. Adikaram, Old Dominion University
M. J. Amaryan, Old Dominion UniversityFollow
S. Bültmann, Old Dominion UniversityFollow
Gail Dodge, Old Dominion UniversityFollow
N. Guler, Old Dominion University
L. B. Weinstein, Old Dominion UniversityFollow

Document Type

Article

Publication Date

2016

DOI

10.1103/PhysRevC.94.045206

Publication Title

Physical Review C

Volume

94

Issue

4

Pages

045206 (1-19)

Abstract

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

Comments

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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

ORCID

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

Repository Citation

CLAS Collaboration; Adhikari, K. P.; Kuhn, S E.; Adikaram, D.; Amaryan, M. J.; Bültmann, S.; Dodge, Gail; Guler, N.; and Weinstein, L. B., "Measurement of Target and Double-Spin Asymmetries for the ep → eπ+(n) Reaction in the Nucleon Resonance Region at Low Q²" (2016). Physics Faculty Publications. 230.
https://digitalcommons.odu.edu/physics_fac_pubs/230