Chiral Lagrangian treatment of pi eta scattering - art. no. 074030

We study pi eta scattering in a model which starts from the tree diagrams o f a non-linear chiral Lagrangian including appropriate resonances. Previous ly, models of this type were applied to pi pi and pi K scattering and were seen to require the existence of light scalar sigma(560) and kappa(900) mes ons and to be consistent with the f(0)(980). The present calculation extend s this to include the a(0)(980), thereby completing a possible nonet of lig ht scalars, all "seen" in the same manner. We note that, at the initial lev el, the pi eta channel is considerably cleaner than the pi pi and pi K chan nels for the study of light scalars. This is because the large competing ef fects of vector meson exchange and "current-algebra" contact terms are abse nt. The simplicity of this channel enables us to demonstrate the closeness of our exactly crossing symmetric amplitude to a related exactly unitary am plitude. The calculation is also extended to higher energies in order to le t us discuss the role played by the a(0)(1450) resonance.