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 $Q^2$

Abstract

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.

arXiv comment20 pages, 15 figures, to appear in Phys. Rev. C

References in corpus (21)

• Unitary Isobar Model - MAID2007
• Measurements of the Proton and Deuteron Spin Structure Functions g1 and g2
• Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction
• Electroexcitation of nucleon resonances
• Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region
• Electromagnetic Meson Production in the Nucleon Resonance Region
• Pion cloud and the $Q^2-$dependence of ${\gamma }^{\ast }N\leftrightarrow \Delta$ transition form factors
• Precision Measurement of the Neutron Spin Asymmetry $A_1^n$ and Spin-Flavor Decomposition in the Valence Quark Region
• Threshold Pion Electroproduction in Chiral Perturbation Theory
• Cross sections and beam asymmetries for $\vev{e}p \to enπ^+$ in the nucleon resonance region for $1.7\le Q^2\le 4.5(GeV{)}^2$
• Single Quark Transition Model Analysis of Electromagnetic Nucleon Resonance Transitions in the [70,1-] Supermultiplet
• First measurement of the helicity asymmetry for $\gamma p\to p{\pi }^0$ in the resonance region
• QED Radiative Corrections in Processes of Exclusive Pion Electroproduction
• Improved description of threshold pion electroproduction in chiral perturbation theory
• Measurement of the Polarized Structure Function ${\sigma }_{L{T}^{\prime }}$ for $p(\vec{e},e^{\prime }{\pi }^{+})n$ in the $\Delta (1232)$ Resonance Region
• Baryon Resonance Analysis from SAID
• Study of polarized-e polarized-p --> e-prime p pi0 in the Delta(1232) mass region using polarization asymmetries
• First Measurement of the Double Spin Asymmetry in $\vec{e}\vec{p}\to e^{\prime }{\pi }^{+}n$ in the Resonance Region
• Kenneth Wilson and lattice QCD
• Lattice QCD: concepts, techniques and some results
• Helicity Asymmetry Measurement for ${\pi }^0$ Photoproduction on the CLAS Frozen Spin Target

Cited by in corpus (6)

• The Spin Structure of the Nucleon
• Jülich-Bonn-Washington Model for Pion Electroproduction Multipoles
• Measurement of the Q^2 Dependence of the Deuteron Spin Structure Function g_1 and its Moments at Low Q^2 with CLAS
• Target and Beam-Target Spin Asymmetries in Exclusive ${\pi }^{+}$ and ${\pi }^{-}$ Electroproduction with 1.6 to 5.7 GeV Electrons
• Measurement of the nucleon spin structure functions for 0.01<$Q^2$<1 GeV${}^2$ using CLAS
• Experimental studies at low $Q^2$ of the spin structure of the nucleon at Jefferson Lab