Nucleon Resonance Properties in Multichannel Approaches

Nucleon resonance properties are compared in different multichannel analyses. The approaches incorporate unitarity and as a minimum include the πN, ππN, ηN and γN asymptotic states. They differ in their descriptions of the background, resonance parameterizations and degree of incorporating theoretical constraints and symmetries, such as analyticity, gauge invariance and chiral symmetry. We find that in most cases the properties of the first resonance in each partial wave are in fair agreement with each other. For each second resonance in a given partial wave the extracted masses may be similar but its properties vary widely. Any evidence for a third resonance in a particular partial wave is tenuous.