We report measurements of target- and double-spin asymmetries for the exclusive channel (e) over right arrow (p) over right arrow -> ep(+)(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 Q(2) range from 0.0065 to 0.35 (GeV/c)(2). The Q(2) access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6 degrees. 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.
Zheng, X., Adhikari, K., Bosted, P., Deur, A., Drozdov, V., El Fassi, L., et al. (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) [10.1103/PhysRevC.94.045206].
Measurement of target and double-spin asymmetries for the ep - →eπ+(n) reaction in the nucleon resonance region at low Q2
COLANERI, LUCA;D'ANGELO, ANNALISA;Lanza, L;PISANO, SILVIA;RIZZO, ALESSANDRO;ZONTA, IRENE
2016-10-19
Abstract
We report measurements of target- and double-spin asymmetries for the exclusive channel (e) over right arrow (p) over right arrow -> ep(+)(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 Q(2) range from 0.0065 to 0.35 (GeV/c)(2). The Q(2) access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6 degrees. 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.