Photoproduction of ηmesons on protons in the resonance region:The background problem and the third S_11 resonance

Abstract

We have constructed an isobar model for the $\eta$-photoproduction on the proton in the energy region up to the photon lab energy $K_0=3$ GeV. The data base involved into the fitting procedure includes precise results for the cross section and for the $T$-asymmetry of the process $\gamma p\to \eta p$ near threshold obtained at MAMI and ELSA as well as recent results for the $\Sigma$-asymmetry and for the angular distribution measured at higher energies in Grenoble and also more recent measurements performed at JLab for the photon energies up to 2 GeV. The model includes twelve nucleon resonances: $S_{11}(1535)$, $S_{11}(1650)$, $S_{11}(1825)$, $P_{11}(1440)$,$P_{13}(1720)$, $D_{13}(1520)$, $D_{15}(1675)$, $F_{15}(1680)$, $F_{17}(1990)$,$G_{17}(2190)$, $G_{19}(2250)$, $H_{19}(2220)$, and the background consisting of the nucleon pole term and the vector meson exchange in the $t$-channel. To explain the observed energy dependence of the integrated cross section, two $s$ -wave resonances, $S_{11}(1650)$ and $S_{11}(1825)$, have to be taken into account along with the dominating $S_{11}(1535)$. The integrated cross section as well as the angular distribution and $\Sigma$ asymmetry predicted by the model are in good agreement with the data. Above the photon energy $K_0=2$ GeV, the calculated cross section exhibits an appreciable dependence on the $\rho$- and $\omega$-meson contribution, whose coupling with nucleons is not well defined. Several versions of extending the model to higher energies are considered.

7 pages, 8 figures, 2 tables, version to appear in Eur.Phys.J.A 22 (2004)

References in corpus (5)

• An isobar model for eta photo- and electroproduction on the nucleon
• A reggeized model for eta and eta-prime photoproduction
• Differential cross section measurement of eta photoproduction on the proton from threshold to 1100 MeV
• Study of N* Production from J/Psi--> p pbar eta
• Excitation of S11 resonances in pion scattering and pion photoproduction on the proton

Cited by in corpus (11)

• Dynamical coupled-channel approach to hadronic and electromagnetic production of kaon-hyperon on the proton
• Photoproduction of eta meson within a coupled-channels K-matrix approach
• Eta and Etaprime Photoproduction on the Nucleon with the Isobar Model EtaMAID2018
• A new $N^{\ast }(1675)$ resonance in the $\gamma N\to \eta N$ reaction
• Study of $\eta$ photoproduction on the proton in a chiral constituent quark approach via one-gluon-exchange model
• Combined study of gamma p to eta p and pi-p to eta n in a chiral constituent quark approach
• $\eta$ production off the proton in a Regge-plus-chiral quark approach
• Fixed-t analyticity as a constraint in single energy partial wave analyses of meson photoproduction reactions
• Energy dependent analysis of eta-meson photoproduction on protons and neutrons without background in the energy region up to 3.4 GeV
• Photoproduction of $\eta$ mesons off the proton for $1.2<E_{\gamma }<4.7$ GeV using CLAS at Jefferson Laboratory
• Final remarks to our study of $\eta$-photoproduction on protons in the resonance region