Photon induced KΛ production on the proton in the low energy region

The associated photoproduction of [Formula: see text] from the proton in the low energy region is studied using an isobar model in which the nonresonant contributions are obtained from the nonlinear 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 nonlinear sigma model. The present model is an extension of the nonlinear 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 ([Formula: see text]) in the [Formula: see text] channel, the hyperon resonances ([Formula: see text]) in the [Formula: see text] channel, and the kaon resonances ([Formula: see text] and [Formula: see text]) in the [Formula: see text] channel having spin [Formula: see text] and mass [Formula: see text][Formula: see text]GeV with a significant branching ratio in [Formula: see text] decay mode, have been considered. The strong and electromagnetic couplings of the [Formula: see text] channel nucleon resonances are taken from experiments while the couplings for the resonances in the [Formula: see text] and [Formula: see text] channels are fitted to reproduce the current data on the associated photoproduction of [Formula: see text] 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.

Non-strange baryons (CLAS)

Baryon spectroscopy is an essential tool in the study of nucleon resonances. The use of polarization observables can greatly clarify the spectrum of broad and overlapping nucleon excitations. The N* program with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility includes experimental studies with linearly- and circularly-polarized tagged-photon beams, longitudinally- and transversely-polarized nucleon targets, and recoil polarizations. An overview of these experimental studies and recent results are presented.