Covariant L-S Scheme for the effective N*NM couplings

Abstract

For excited nucleon states $N^{\ast }$ of arbitrary spin coupling to nucleon (N) and meson (M), we propose a Lorentz covariant orbital-spin (L-S) scheme for the effective $N^{\ast }NM$ couplings. To be used for the partial wave analysis of various $N^{\ast }$ production and decay processes, it combines merits of two conventional schemes, {\sl i.e.}, covariant effective Lagrangian approach and multipole analysis with amplitudes expanded according to angular momentum L. As examples, explicit formulae are given for $N^{\ast }\to N\pi$, $N^{\ast }\to N\omega$ and $\psi \to N^{\ast }\bar{N}$ processes which are under current experimental studies.

Comments: Postscript file, 14 pages