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This content will become publicly available on October 19, 2017

Title: Measurement of target and double-spin asymmetries for the $$\vec e\vec p\to e\pi^+ (n)$$ reaction in the nucleon resonance region at low $Q^2$

We report measurements of target- and double-spin asymmetries for the exclusive channel $$\vec e\vec p\to e\pi^+ (n)$$ 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 NH$_3$ 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 $$6^\circ$$. 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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Publication Date:
OSTI Identifier:
1329529
Report Number(s):
JLAB-PHY--16-2307; DOE/OR/23177--3890; arXiv:1607.03924
Journal ID: ISSN 2469-9985; PRVCAN
Grant/Contract Number:
AC05-06OR23177; ST/L005719/1; GR/T08708/01
Type:
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 94; Journal Issue: 4; Journal ID: ISSN 2469-9985
Publisher:
APS
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Contributing Orgs:
CLAS Collaboration
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS