Chiral Breit-Wigner

Chiral symmetry and unitarization are combined into generalized Breit-Wigner expressions describing scalar resonances, which contain free parameters and allow flexible descriptions of masses, widths and pole positions. This theoretical tool is especially designed to be used in analyses of low-energy data.Comment: Talk given at the XI International Conference on Hadron Spectroscopy, Rio de Janeiro, Brazil, August 200

TWO-PION EXCHANGE NUCLEAR POTENTIAL - CHIRAL CANCELLATIONS

We show that chiral symmetry is responsible for large cancellations in the two-pion exchange nucleon-nucleon interaction, which are similar to those occuring in free pion-nucleon scattering.Comment: REVTEX style, 5 pages, 3 PostScrip figures compressed, tarred and uuencode