On the cross section ratio sigma_n/sigma_p in eta photoproduction

Abstract

The recently discovered enhancement of eta photoproduction on the quasi-free neutron at energies around sqrt(s)~1.67 GeV is addressed within a SU(3) coupled channel model. The quasi-free cross sections on proton and neutron, sigma_n and sigma_p, can be quantitatively explained. In this study, the main source for the peak in sigma_n/sigma_p is a coupled channel effect in S-wave that explains the dip-bump structure in gamma n --> eta n. In particular, the photon coupling to the intermediate meson-baryon states is important. The stability of the result is extensively tested and consistency with several pion- and photon-induced reactions is ensured.

Version accepted by Phys. Lett. B

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• Eta-meson production in the resonance energy region
• Photocouplings at the Pole from Pion Photoproduction
• Quasi-free photoproduction of eta-mesons off the deuteron
• Pion photoproduction in a dynamical coupled-channels model
• $K^{+}\Lambda$ and $K^{+}{\Sigma }^0$ photoproduction with fine center-of-mass energy resolution
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• Quasifree photoproduction of $\eta$ mesons off protons and neutrons
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• The phase and pole structure of the N*(1535) in piN-->piN and gammaN-->piN
• $\eta$ photoproduction on the quasi-free nucleons in the chiral quark model
• Light baryon resonances from a coupled-channel study including $\mathbf{K\Sigma }$ photoproduction
• Jülich-Bonn-Washington Model for Pion Electroproduction Multipoles
• Evidence for Narrow N*(1685) Resonance in Quasifree Compton Scattering on the Neutron
• $\bar{K}+N\to K+\Xi$ reaction and $S=-1$ hyperon resonances
• Finite volume effects and quark mass dependence of the N(1535) and N(1650)
• Insight into the narrow structure in {\boldmath{$\eta$}}-photoproduction on the neutron from helicity dependent cross sections
• Quasi-free photoproduction of eta-mesons off 3He nuclei
• Eta-photoproduction in a gauge-invariant chiral unitary framework
• Evaluation of the polarization observables I^S and I^C in the reaction gamma p --> pi^0 eta p
• Evidence for the J^p=1/2^+ narrow state at 1650 MeV in the photoproduction of KLambda
• Helicity-dependent cross sections and double-polarization observable E in eta photoproduction from quasi-free protons and neutrons
• Role of the $N^{\ast }(1535)$ in the ${\Lambda }_c^{+}\to {\bar{K}}^0\eta p$ decay
• Coupled-channel analysis of pion- and eta-electroproduction with the Jülich-Bonn-Washington model
• Neutral pion photoproduction on the nucleon in a chiral quark model
• Evidence for narrow resonant structures at $W\approx 1.68$ and $W\approx 1.72$ GeV in real Compton scattering off the proton
• Correlations of $\mathbf{\pi N}$ Partial Waves for Multi-Reaction Analyses
• Photoproduction of eta mesons from the neutron: cross sections and double polarization observable E
• $K^0\Lambda$ photoproduction off the neutron with nucleon resonances
• Photo- and electro-production of narrow exotic states: from light quarks to charm and up to bottom
• Is there a narrow $N(1685)$?
• Observation of Narrow $N^{+}(1685)$ and $N^0(1685)$ Resonances in $\gamma N\to \eta \pi N$ Reactions
• High-precision Measurements of piP Elastic Differential Cross Sections in the Second Resonance Region
• Effects of nucleon resonances on $\eta$ photoproduction off the neutron reexamined
• Eta and kaon production in a chiral quark model
• On strange SU(3) partners of Theta+
• Search for narrow resonances in $\pi p$ elastic scattering from the EPECUR experiment
• Evidence of the non-strange partner of pentaquark from the elementary $K^{+}\Lambda$ photoproduction
• New Narrow $N(1685)$ and $N(1726)$? Remarks on the Interpretation of the Neutron Anomaly as an Interference Phenomenon
• On Narrow Nucleon Excitation N*(1685)
• Search for the $N$(1685) in $\eta \pi$-Photoproduction
• New narrow N*(1685) resonance: review of observations
• New narrow nucleon resonances $N^{\ast }(1685)$ and $N^{\ast }(1726)$ within the chiral quark-soliton model
• The neutron anomaly in the gamma N --> eta N cross section through the looking glass of the flavour SU(3) symmetry
• Recent Developments on Hadron Interaction and Dynamically Generated Resonances
• Notes on New Narrow N*