Indications on the g-Like Singularities in the Complex J-Plane.

Abstract

We present a sum rule which is satisfied by the amplitude of the forward π- Ν charge-exchange scattering. It relates the relevant high-energy parameters to lower-energy data. In contrast with other dispersion sum rules, the very-low-energy data contribute here with much more weight. This sum rule provides a new insight into the structure of the singularities in the complex J-plane. We find that, besides the g-pole, other singularities must be present to obtain consistency, and a rough indication of their structure is obtained.