G-Conjugation and the Group-Space of the Proper Lorentz Group

An earlier proposal of the author for the incorporation of isotopic spin into the foundations of the theory of spin ½ particles, based upon a consideration of the group-space of the proper Lorentz group, is here shown to require a certain definite conception of the essentially spatiotemporal character of all "internal" elementary particle phenomena such as isotopic spin. It is further shown that according to this proposal the particular spatiotemporal character of the 3-parameter group of isotopic spin rotations of a strongly interacting charge doublet is identical with that of another 3-parameter group of spinor transformations recently applied by Pauli to the neutrino. It thus follows that for leptons in general there should exist an analog of isotopic spin rotations, which must be expected to differ from the latter, however, in its physical interpretation. Through a similar generalization of the notion of $G$-conjugation, a fundamental criterion is then shown to be available for the classification of all spin ½ particles into the two families of leptons and baryons, respectively.