Description of a Particle with Arbitrary Mass and Spin

Abstract

A Lorentz covariant description of a particle and antiparticle with spin $s=0, \frac{1}{2}, 1, \cdots$ and finite rest mass is given in this paper. The wave function has $2(2s+1)\mathrm{}$ components so that no auxiliary conditions are needed. The basic idea is to postulate the rest-system Hamiltonian and make the Lorentz transformation to the laboratory system. An algorithm which is a generalization of the Foldy-Wouthuysen transformation is found for constructing the laboratory-system Hamiltonian and polarization operators.