We present an effective-Lagrangian description for forward-angle $K^{+}\Lambda$ photoproduction from the proton, valid for photon lab energies from threshold up to $16\mathrm{GeV}$. The high-energy part of the amplitude is modeled in terms of t-channel Regge-trajectory exchange. The sensitivity of the calculated observables to the Regge-trajectory phase is investigated in detail. The model is extended toward the resonance region by adding a number of s-channel resonances to the t-channel background. The proposed hybrid “Regge-plus-resonance” (RPR) approach allows one to exploit the $p(\gamma ,K^{+})\Lambda$ data in their entirety, resulting in stronger constraints on both the background and resonance couplings. The high-energy data can be used to fix the background contributions, leaving the resonance couplings as the sole free parameters in the resonance region. We compare various implementations of the RPR model and explore to what extent the description of the data can be improved by introducing the “new” resonances $D_{13}(1900)$ and $P_{11}(1900)$. Despite its limited number of free parameters, the proposed RPR approach provides an efficient description of the $p(\gamma ,K^{+})\Lambda$ dynamics in and beyond the resonance region.

• Received 19 October 2005

DOI:https://doi.org/10.1103/PhysRevC.73.045207