5 research outputs found
Two-spinor description of massive particles and relativistic spin projection operators
On the basis of the Wigner unitary representations of the covering group
ISL(2,C) of the Poincar\'{e} group, we obtain spin-tensor wave functions of
free massive particles with arbitrary spin. The wave functions automatically
satisfy the Dirac-Pauli-Fierz equations. In the framework of the two-spinor
formalism we construct spin-vectors of polarizations and obtain conditions that
fix the corresponding relativistic spin projection operators (Behrends-Fronsdal
projection operators). With the help of these conditions we find explicit
expressions for relativistic spin projection operators for integer spins
(Behrends-Fronsdal projection operators) and then find relativistic spin
projection operators for half integer spins. These projection operators
determine the nominators in the propagators of fields of relativistic
particles. We deduce generalizations of the Behrends-Fronsdal projection
operators for arbitrary space-time dimensions D>2.Comment: 34 page
Generalization of the Bargmann-Wigner construction for infinite spin fields
We develop a generalization of the Wigner scheme for constructing the
relativistic fields corresponding to irreducible representations of the
four-dimensional Poincar\'{e} group with infinite spin. The fields are
parameterized by a vector and an additional commuting vector or spinor
variable. The equations of motion for fields of infinite spin are derived in
both formulations under consideration.Comment: 1+29 pages, v2: typos correcte