Isobar formalism and one-pion-exchange partial-wave cross sections in πN → ππN

This work is a prelude to a phase-shift analysis of πN → ππN which we are presently performing. We here review the partial-wave isobar formalism for the above process and introduce the notation being used in our analysis. We compute the partial-wave projections of the one-pion-exchange diagrams because we hope to use the high-partial-wave contributions of these diagrams, which are not modified by the interactions, to remove phase ambiguities in the partial waves being varied. A study of the low partial waves, even though they violate unitarity badly, gives modest insights into the results of previous partial-wave analyses