Preliminary results of a study of quenched chiral logarithms at β = 5.7 are presented. Four independent determinations of the quenched chiral log parameter δ are obtained. Two of these are from estimates of the η′ mass, one from the residue of the hairpin diagram and the other from the topological susceptibility combined with the Witten-Veneziano formula. The other two determinations of δ are f...

We investigate the ∆S = 1 effective weak chiral Lagrangian within the framework of the chiral quark model. Starting from the effective four-quark operators, we derive the effective weak chiral action by integrating out the constituent quark fields. Employing the derivative expansion, we obtain the effective weak chiral Lagrangian to order O(p4). We examine the contributions of the order O(Nc) t...

The chiral SU(3) quark model is extended to include coupling between vector chiral field and quarks. By using this model, the phase shifts of NN scattering for different partial waves are studied. The results are very similar to those of the chiral SU(3) quark model calculation, in which one gluon exchange (OGE) plays dominate role in the short range part of the quark-quark interactions. Only i...

We have studied in perturbative QCD all independent helicity amplitudes describing the photoproduction of light vector mesons at large t. We found a new hard production mechanism which is related to the possibility for a real photon to fluctuate into a massless q ¯ q pair in a chiral-odd spin configuration. Each helicity amplitude is given as a sum of chiral-even contribution (when the heliciti...