Analysis of Multichannel Reactions

A method for analysis of multichannel reaction data is presented. We consider a system of $n$ strongly coupled two-body channels in a particular "partial wave." The energy dependence of the cross sections is treated in the effective range approximation; the corrections to the scattering amplitudes due to mass differences between isotopic spin multiplets and Coulomb scattering are included. "Uncoupled" amplitudes, which would describe the scattering in the absence of influences of one of the channels, are introduced. Relations between these uncoupled phases and the actual amplitudes are derived (in a nonperturbative manner). The use of the uncoupled phase procedure, in conjunction with an effective-range analysis, to test certain theories of strong interactions is discussed.