学术文献库

The associated photoproduction of $KΛ$ from the proton in the low energy region is studied using an isobar model in which the non-resonant contributions are obtained from the non-linear sigma model with chiral SU(3) symmetry which predicts, in a natural way, the contact term with its coupling strength along with the coupling strengths of the various Born terms predicted by the non-linear sigma model. The present model is an extension of the non-linear sigma model with chiral SU(2) symmetry, used earlier to study the photo, electro, and neutrino productions of pions. In the resonance sector, the contributions from the well established nucleon resonances ($R$) in the $s$ channel, the hyperon resonances ($Y^{*}$) in the $u$ channel, and the kaon resonances ($K^{*}$ and $K_{1}$) in the $t$ channel having spin $\le \frac{3}{2}$ and mass $<2$ GeV with a significant branching ratio in $KΛ$ decay mode, have been considered. The strong and electromagnetic couplings of the $s$ channel nucleon resonances are taken from experiments while the couplings for the resonances in the $t$ and $u$ channels are fitted to reproduce the current data on the associated photoproduction of $KΛ$ in this energy region. The numerical results are presented for the total and differential cross sections and are compared with the available experimental data from CLAS and SAPHIR as well as with some of the recent theoretical models.