On the "old" and "new" relativistic wave equations for the particle having spin s=3/2

Abstract

Relativistic wave equation of motion without redundant components for the particle having spin 3/2 has been considered. In order to show the newness a comparison with the known equations for the spin s=3/2 field is given. Therefore, the brief review of the relativistic wave equations for the particle with spin s=3/2 is given. In our equation the wave function for the particle-antiparticle doublet has only 8 components. The consideration is carried out both at the level of relativistic quantum mechanics and at the level of local field theory. The extended Foldy--Wouthuysen transformation, which gives the operator link between these two levels is suggested.