Semi-leptonic weak and electromagnetic interactions with nuclei: isoelastic processes

A one-body density matrix formalism is presented for studies of isoelastic processes, that is, for semi-leptonic weak and electromagnetic interactions involving the members of a nuclear ground-state isospin doublet. Relationships involving density matrices are given for the general case and then specialized to the systems 3H-3He and 11B-11C, where data on conventional electromagnetic and weak interactions provide stringent constraints on the form of the density matrix. Predictions are then given for charge-changing and neutral current neutrino reactions. The effects of changes in the weak coupling constants and of second-class tensor currents on these processes are discussed. (Auth.)