Effects of N(2000)5/2+ on γp→K+Λ(1405)

Abstract

The photoproduction reaction of $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}\mathrm{\ensuremath{\Lambda}}(1405)$ is investigated based on an effective Lagrangian approach at the tree-level approximation with the purpose of understanding the reaction mechanism and extracting the resonance contents and the associated resonance parameters in this reaction. Apart from the $t$-channel $K$ and ${K}^{*}$ exchanges, $s$-channel nucleon ($N$) exchange, $u$-channel $\mathrm{\ensuremath{\Sigma}}, \mathrm{\ensuremath{\Lambda}}$, and $\mathrm{\ensuremath{\Lambda}}(1405)$ exchanges, and generalized contact term, the exchanges of a minimum number of $N$ resonances in the $s$ channel are taken into account in constructing the reaction amplitudes to describe the experimental data. It is found that by introducing the $N(2000){5/2}^{+}$ resonance exchange in the $s$ channel, one can reproduce the most recent differential cross-section data from the CLAS Collaboration quite well. Further analysis shows that the cross sections of $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}\mathrm{\ensuremath{\Lambda}}(1405)$ at high energies are dominated by the $t$-channel $K$ exchange, while the contributions from the $s$-channel $N$ and $N(2000){5/2}^{+}$ exchanges are rather significant to the cross sections in the near-threshold energy region. Predictions for the beam and target asymmetries for $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}\mathrm{\ensuremath{\Lambda}}(1405)$ are given.