| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1839655 | Nuclear Physics A | 2006 | 11 Pages |
The γp→ϕηp reaction is studied in the kinematic region where the ηp final state originates dominantly from the decay of the N∗(1535) resonance. The threshold laboratory photon energy for this reaction (at the peak of the S11 resonance) is . We will discuss it somewhat above threshold, at , in order to reach lower (absolute) values of the squared 4-momentum transfer from the initial photon to the final ϕ-meson. In these conditions, we expect the t-channel π0- and η-meson exchanges to drive the dynamics underlying the γp→ϕηp process. The initial photon dissociates into the final ϕ-meson and a virtual pseudoscalar meson (π0 or η). The virtual pseudoscalar meson scatters from the proton target to produce the final ηp state. The π0p→ηp and ηp→ηp amplitudes are derived in the framework of a coupled-channel effective field theory of meson-baryon scattering. We found the η-meson exchange to be largely dominant. The η–π0 interference is of the order of 20–30%. The sign of this term is not known and has a significant influence on the results. The πN→ηN amplitude being largely determined by data on the π−p→ηn reaction, we found that the γp→ϕηp reaction cross section is rather directly related to the η-nucleon scattering amplitude in the N∗(1535) resonance region. Accurate data on the γp→ϕηp process would therefore put additional constraints on this still poorly known amplitude.
