Nonleptonic decays: Amplitude analysis and supermultiplet schemes

We give best covariant amplitude decompositions for two-body decay processes involving ground state hadrons ($0^{-},1^{-},{1\mathrm{/}2}^{+},{3\mathrm{/}2}^{+}$) and show how these are simply related to helicity amplitudes. After discussing how electromagnetic interactions are incorporated via meson dominance in a relativistic supermultiplet scheme, we extend the analysis to weak flavour changing nonleptonic processes. Such weak interactions are described by three generic amplitudes, which we estimate according to the rules of calculation within covariant SU(2N${}_f$).