https://doi.org/10.1140/epja/i2004-10024-x
Photoproduction of
-mesons on protons in the resonance region: The background problem and the third S
11-resonance
Institute for Nuclear Physics, Tomsk Polytechnic University, P.O. Box 25, 634050, Tomsk, Russia
* e-mail: trs@npi.tpu.ru
We have constructed an isobar model for the -photoproduction on the proton in the energy region up to the photon lab energy K
0 = 3 GeV. The database involved into the fitting procedure includes precise results for the cross-section and for the T-asymmetry of the process
near threshold obtained at MAMI and ELSA as well as recent results for the
-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
-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
- and
-meson contribution, whose coupling with nucleons is not well defined. Several versions of extending the model to higher energies are considered.
© Società Italiana di Fisica and Springer-Verlag, 2004