Kaon photoproduction: Background contributions, form factors, and missing resonances

The photoproduction $p(\ensuremath{\gamma}{,K}^{+})\ensuremath{\Lambda}$ process is studied within a field-theoretic approach. It is shown that the background contributions constitute an important part of the reaction dynamics. We compare predictions obtained with three plausible techniques for dealing with these background contributions. It appears that the extracted resonance parameters drastically depend on the applied technique. We investigate the implications of the corrections to the functional form of the hadronic form factor in the contact term, recently suggested by Davidson and Workman [Phys. Rev. C 63, 025210 (2001)]. The role of background contributions and hadronic form factors for the identification of the quantum numbers of ``missing'' resonances is discussed.