Multipoles model for K+ Λ photoproduction on the nucleon reexamined

We have updated our previous multipoles model for the kaon photoproduction process γp→K+Λ by using the recently available experimental data, including the new CLAS 2016 data, and up-to-date information on the nucleon resonance properties provided by the Particle Data Group (PDG). The background and resonance parameters are extracted by fitting the calculated observables to nearly 7400 experimental data points and constraining the resonance parameters within the PDG error bars. The model can nicely reproduce the experimental data with χ2/Ndof=1.63. Different from the previous result, the present analysis finds the N(1650)S11, N(1720)P13, and N(1900)P13 states to be the most important resonances in the process. Excluding these states in the model increases the value of χ2 tremendously. As in our previous model, however, the contribution of the N(1710)P11 state in minimizing χ2 is found to be less significant. By including the new CLAS 2016 data in the fitting database and refitting the calculated observables to nearly 9000 data points, the χ2/Ndof increases to 2.88. In spite of the increase of χ2, the agreement of model calculations with the new data is improved and the conclusion on the most important resonances in the process remains the same. An extensive comparison between the result of model calculations and experimental data on differential cross section, single polarization observables P, T, and Σ, as well as double polarization observables Cx, Cz, Ox′, Oz′, Ox, and Oz, is presented in this paper.