CHIRAL POLES AND ZEROS AND THE ROLE OF THE LEFT HAND CUT

It has been recently claimed that the Inverse Amplitude Method provide s a reliable unitarisation of Chiral Perturbation Theory allowing reso nance poles to be accurately uncovered. We illustrate the sensitivity of these claims to the treatment of the Adler zero and to assumptions about the left hand cut (and hence about the underlying exchange force s). Previously favoured methods are shown to mistreat the Adler zeros and violate crossing symmetry casting doubt on the precision of their phenomenology. A more reliable solution is proposed. This places the I nverse Amplitude Method on a firmer basis.