First Measurement of the Double Spin Asymmetry in $\vec{e}\vec{p}\to e^{\prime }{\pi }^{+}n$ in the Resonance Region

Abstract

The double spin asymmetry in the $\vec{e}\vec{p}\to e^{\prime }{\pi }^{+}n$ reaction has been measured for the first time in the resonance region for four-momentum transfer $Q^2=0.35-1.5$ GeV${}^2$. Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH${}_3$ target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with $Q^2$ of the helicity asymmetry $A_1$ for the $F_{15}(1680)$ resonance than expected from the analysis of the unpolarized data.

arXiv comment6 pages, 3 figures

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• The e p -> e' p eta reaction at and above the S11(1535) baryon resonance
• Electromagnetic transition form factors of negative parity nucleon resonances
• Electroproduction of the S11(1535) Resonance at High Momentum Transfer
• Measurement of the recoil polarization in the p (\vec e, e' \vec p) pi^0 reaction at the Δ(1232) resonance

Cited by in corpus (16)

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• Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance
• Study of polarized-e polarized-p --> e-prime p pi0 in the Delta(1232) mass region using polarization asymmetries
• First measurement of target and double spin asymmetries for polarized e- polarized p --> e p pi0 in the nucleon resonance region above the Delta(1232)
• 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 $Q^2$
• Q^2-evolution of nucleon-to-resonance transition form factors in a QCD-inspired vector-meson-dominance model
• Target and Beam-Target Spin Asymmetries in Exclusive Pion Electroproduction for $Q^2>1$ GeV${}^2$. I. $ep\to e{\pi }^{+}n$
• Target and Beam-Target Spin Asymmetries in Exclusive ${\pi }^{+}$ and ${\pi }^{-}$ Electroproduction with 1.6 to 5.7 GeV Electrons
• Spin Response of the Nucleon in the Resonance Region
• Relativistically invariant analysis of $\Delta$--isobar production in deuteron electrodisintegration: $e^{-}+d\to e^{-}+\Delta +N:$ general analysis of polarization effects
• Status of Spin Physics - Experimental Summary