Q^2 Dependence of the S_{11}(1535) Photocoupling and Evidence for a P-wave resonance in eta electroproduction

Abstract

New cross sections for the reaction $ep\to e^{\prime }\eta p$ are reported for total center of mass energy $W$=1.5--2.3 GeV and invariant squared momentum transfer $Q^2$=0.13--3.3 GeV${}^2$. This large kinematic range allows extraction of new information about response functions, photocouplings, and $\eta N$ coupling strengths of baryon resonances. A sharp structure is seen at $W\sim$ 1.7 GeV. The shape of the differential cross section is indicative of the presence of a $P$-wave resonance that persists to high $Q^2$. Improved values are derived for the photon coupling amplitude for the $S_{11}$(1535) resonance. The new data greatly expands the $Q^2$ range covered and an interpretation of all data with a consistent parameterization is provided.

31 pages, 9 figures

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• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The Cosmological Parameters 2006
• Measurement of the N to Delta(1232) Transition at High Momentum Transfer by pi0 Electroproduction

Cited by in corpus (64)

• Baryon spectroscopy
• Explanation and Prediction of Observables using Continuum Strong QCD
• Progress Toward Understanding Baryon Resonances
• Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction
• Studies of Nucleon Resonance Structure in Exclusive Meson Electroproduction
• Electroexcitation of nucleon resonances
• Photoproduction of $\eta$ and $\eta \prime$ Mesons off Protons
• New Results from the Studies of the $N(1440)1/2^{+}$, $N(1520)3/2^{-}$, and $\Delta (1620)1/2^{-}$ Resonances in Exclusive $ep\to e^{\prime }{p}^{\prime }{\pi }^{+}{\pi }^{-}$ Electroproduction with the CLAS Detector
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• A systematic study of longitudinal and transverse helicity amplidutes in the hypercentral Constituent Quark Model
• Nucleon electromagnetic form factors and electroexcitation of low lying nucleon resonances in a light-front relativistic quark model
• Quasi-free photoproduction of eta-mesons off the deuteron
• Cross sections and beam asymmetries for $\vev{e}p \to enπ^+$ in the nucleon resonance region for $1.7\le Q^2\le 4.5(GeV{)}^2$
• Model Analysis of the $ep\to e{p}^{\prime }{\pi }^{+}{\pi }^{-}$ Electroproduction Reaction on the Proton
• Quasifree photoproduction of $\eta$ mesons off protons and neutrons
• Transition form factors of the N*(1535) as a dynamically generated resonance
• Structure of the nucleon's low-lying excitations
• Measurements of $ep\to e^{\prime }{\pi }^{+}n$ at W = 1.6 - 2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS
• Empirical transverse charge densities in the nucleon-to-P11(1440) transition
• Photoproduction of mesons off nuclei
• The role of the $qqqq\bar{q}$ components in the electromagnetic transition ${\gamma }^{\ast }N\to N^{\ast }(1535)$
• A covariant model for the gamma N -> N(1535) transition at high momentum transfer
• Hadron structure at low Q^2
• Strong QCD Insights from Excited Nucleon Structure Studies with CLAS and CLAS12
• Electroproduction of Eta Mesons in the S11(1535) Resonance Region at High Momentum Transfer
• Electroproduction of the N*(1535) resonance at large momentum transfer
• Electroproduction of the $N^{\ast }(1535)$ nucleon resonance in QCD
• Measurements of $ep\to e^{\prime }{\pi }^{+}{\pi }^{-}{p}^{\prime }$ Cross Sections with CLAS at $1.40<W<2.0$ GeV and $2.0<Q^2<5.0$ GeV${}^2$
• Electroproduction of p π^{+} π^{-} off protons at 0.2<Q^{2}<0.6 GeV^{2} and 1.3<W<1.57 GeV with CLAS
• Photoproduction of ${\eta }^{\prime }$-mesons off the deuteron
• Electromagnetic Transition Form Factors of Baryon Resonances
• Nucleon resonance contributions to unpolarised inclusive electron scattering
• Spectrum and structure of octet and decuplet baryons and their positive-parity excitations
• Dynamical diquarks in the ${\mathbf{\gamma }}^{(\ast )}\mathbf{p}\to \mathbf{N}(1535){\frac{1}{2}}^{-}$ transition
• Finite volume effects and quark mass dependence of the N(1535) and N(1650)
• Results from the N* program at JLab
• Studies of N^* structure from the CLAS meson electroproduction data
• Quasi-free photoproduction of eta-mesons off 3He nuclei
• 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
• Coupled-channel analysis of pion- and eta-electroproduction with the Jülich-Bonn-Washington model
• Measurements of the ${\gamma }_{v}p\to p^{\prime }{\pi }^{+}{\pi }^{-}$ cross section with the CLAS detector for $0.4$ GeV${}^2$ $<Q^2<$ $1.0$ GeV${}^2$ and $1.3$ GeV $<W<$ $1.825$ GeV
• Transition form factors and helicity amplitudes for electroexcitation of negative- and positive parity nucleon resonances in a light-front 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${}^2$
• Resonant contributions to inclusive nucleon structure functions from exclusive meson electroproduction data
• N* Experiments and their Impact on Strong QCD Physics
• Photoproduction of eta mesons from the neutron: cross sections and double polarization observable E
• Recoil polarization and beam-recoil double polarization measurement of ηelectroproduction on the proton in the region of the S_{11}(1535) resonance
• Nucleon Resonance Physics
• Electroexcitation of nucleon resonances in a light-front relativistic quark model
• Updates on the Studies of $N^{\ast }$ Structure with CLAS and the Prospects with CLAS12
• Investigation of the anomaly in eta-photoproduction off the neutron
• The decays ${\Lambda }_{b,c}\to N^{\ast }l\nu$ in QCD
• Assessing the theory-data tension in neutrino-induced charged pion production: the effect of final-state nucleon distortion
• Evaluation of the inclusive electron scattering observables in the resonance region from the experimental data
• Charged current (anti)neutrino induced eta production off the nucleon
• Meson Production and Baryon Resonances at CLAS
• The N* Physics Program at Jefferson Lab
• Photo- and Electron-Production of Mesons on Nucleons and Nuclei
• The Jlab Upgrade - Studies of the Nucleon with CLAS12
• Light-cone sum rule approach for Baryon form factors
• Helicity amplitudes of $N(1520)$ and $N(1535)$ including pentaquark components
• Probing the nucleon structure with CLAS
• Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles