
Accession Number : AD0276215
Title : SYMMETRY PROPERTIES OF THE SMATRIX WITH APPLICATION TO RESONANCE REACTIONS
Corporate Author : CARNEGIE INST OF TECH PITTSBURGH PA
Personal Author(s) : DAVIES,K.T.R. ; BARANGER,M.
Report Date : DEC 1962
Pagination or Media Count : 1
Abstract : Symmetry relations of the Swave, Nchannel Smatrix are rederived and applied to a study of its structure in the vicinity of resonances, both away from and near thresholds. A resonance is defined as a pole of the Smatrix. For an isolated pole far from any threshold, the Smatrix can be expressed as the sum of a resonance factorable matrix and a nondiagonal, background matrix, a wellknown result. The parametrization of this expression is discussed. Two types of threshold resonances are considered, corresponding to one and two poles of S respectively. For both cases, the Smatrix again has resonance and background contributions, but the offdiagonal elements involving the opening channel have no background The twopole threshold resonance obeys the standard BreitWigner formula, while the onepole case has a different behavior, which can only be obtained from the BreitWigner expression by making certain reduced widths infinite. Unitarity and symmetry relations impose some interesting restrictions on the distribution of poles and the shape of cross sections near threshold. Results are illustrated. (Author)
Descriptors : *POLARIZATION, *RESONANCE SCATTERING, MATRICES(MATHEMATICS), RESONANCE
Distribution Statement : APPROVED FOR PUBLIC RELEASE