On the isobaric spin and the scattering matrix

The isobaric spin and the scattering matrix are fundamental nuclear physics concepts invented by Werner Heisenberg. The cardinal impact of the Heisenberg concepts on historical developpement of nuclear physics and other quantum and classical physics branches is discussed in this communication. Heisenberg in physics is synonymous to monumental scientific creations, namely: -'Creation of quantum mechanics' (Nobel Prize, 1932), -'Heisenberg relations', or 'Heisenberg inequalities' or 'Uncertainty principle' or 'Indeterminacy principle', - Basis for Copenhagen interpretation of Quantum Mechanics, -'world formula', - Project for a unitary theory representing all existing particles. Heisenberg does signify also important/cardinal contributions to many fields of physics as follows: - hydrodynamical theory of turbulence, (Dissertation, Sommerfeld); - theory of ferromagnetism; - study of cosmic rays; - nuclear physics. Heisenberg has invented two nuclear physics concepts, isobaric spin and scattering matrix which became cornerstones of the two main fields of the nuclear theory, namely, the nuclear structure (nuclear spectroscopy) and the nuclear reactions. This communication intends to illustrate the impact of the Heisenberg concepts on developpement of nuclear physics. (author)