Recoil Polarization for Delta Excitation in Pion Electroproduction

Abstract

We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q^2=1.0 (GeV/c)^2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re(S1+/M1+)=-(6.84+/-0.15)% and Re(E1+/M1+)=-(2.91+/-0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and sp truncation.

5 pages, 2 figures, for PRL

References in corpus (3)

• Proton elastic form factor ratios to $Q^2$ = 3.5 GeV${}^2$ by polarization transfer
• Investigation of the conjectured nucleon deformation at low momentum transfer
• The N to Delta electromagnetic transition form factors from Lattice QCD

Cited by in corpus (48)

• Unitary Isobar Model - MAID2007
• Electromagnetic excitation of the Delta(1232)-resonance
• Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction
• Studies of Nucleon Resonance Structure in Exclusive Meson Electroproduction
• Electroexcitation of nucleon resonances
• Electromagnetic Excitation of Nucleon Resonances
• Measurement of the N to Delta(1232) Transition at High Momentum Transfer by pi0 Electroproduction
• Extraction and Interpretation of gamma N --> Delta Form Factors within a Dynamical Model
• Nucleon electromagnetic form factors and electroexcitation of low lying nucleon resonances in a light-front relativistic quark model
• Cross sections and beam asymmetries for $\vev{e}p \to enπ^+$ in the nucleon resonance region for $1.7\le Q^2\le 4.5(GeV{)}^2$
• Dynamical coupled-channels analysis of 1H(e,e'pi)N reactions
• Measurements of $ep\to e^{\prime }{\pi }^{+}n$ at W = 1.6 - 2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS
• Measurement of the LT-asymmetry in π^0 electroproduction at the energy of the Δ(1232) resonance
• Determination of quadrupole strengths in the gamma*p-->Delta(1232) transition at Q2= 0.20 (GeV/c)2
• Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance
• Jülich-Bonn-Washington Model for Pion Electroproduction Multipoles
• Large-$N_c$ relations for the electromagnetic N to Delta(1232) transition
• Electromagnetic Transition Form Factors of Baryon Resonances
• Dynamical Models of the Excitations of Nucleon Resonances
• Results from the N* program at JLab
• Neutral Pion Electroproduction in the Resonance Region at High $Q^2$
• Angular dependence of recoil proton polarization in high-energy γd \to p n
• Measurement of the Polarized Structure Function ${\sigma }_{L{T}^{\prime }}$ for Pion Electroproduction in the Roper Resonance Region
• 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)
• Electroexcitation of nucleon resonances of the [70,1-] multiplet in a light-front relativistic quark model
• Study of nucleon resonances with electromagnetic interactions
• Amplitude reconstruction from complete electroproduction experiments and truncated partial-wave expansions
• Coupled-channel analysis of pion- and eta-electroproduction with the Jülich-Bonn-Washington model
• Electroexcitation of the ${\Delta }^{+}(1232)$ at low momentum transfer
• Measurements of the γ* p --> Δ(1232) reaction at low Q2
• Electroexcitation of the Delta(1232)3/2+ and Delta(1600)3/2+ in a light-front relativistic quark model
• Exclusive ${\mathbf{\pi }}^0\mathbf{p}$ electroproduction off protons in the resonance region at photon virtualities 0.4~GeV${}^2$ $\le {\mathbf{Q}}^2\le 1$~GeV${}^2$
• Virtual Compton Scattering measurements in the ${\gamma }^{\ast }N\to \Delta$ transition
• Baryon transition form factors at the pole
• Impact of JLab data on the determination of GPDs at zero skewness and new insights from transition form factors $N\to \Delta$
• Electroexcitation of nucleon resonances in a light-front relativistic quark model
• Q^2-evolution of nucleon-to-resonance transition form factors in a QCD-inspired vector-meson-dominance model
• Global Data-Driven Determination of Baryon Transition Form Factors
• Accuracy of traditional Legendre estimators of quadrupole ratios for the N to Delta transition
• Zero-Mode Contribution in Nucleon-Delta Transition
• Electromagnetic form factors of the Delta(1232) in Dual-Large N_c QCD
• Gauge- and point-invariant vertices of nucleon-to-resonance interactions
• Low-Q^2 scaling behavior of the form-factor ratios for the NΔ(1232)-transition
• Measurement of the Partial Cross Sections s(TT), s(LT) and [s(T)+epsilon*s(L)] of the p(e,e' pi+)n Reaction in the Delta(1232) Resonance
• The N* Physics Program at Jefferson Lab
• Pion electroproduction measurements in the nucleon resonance region
• Probing the nucleon structure with CLAS
• Single photo and electroproduction of pions at EBAC@JLAB