Eur. Phys. J. A (2006) 29: 289-306
https://doi.org/10.1140/epja/i2005-10315-8

Hadron Physics

Spin- beyond the Rarita-Schwinger framework

¹ Insituto de Fisica, Universidad de Guanajuato, Lomas del Bosque 103, Fracc. Lomas del Campestre, 37150, Leon, Guanajuato, Mexico
² Instituto de Fisica, UASLP, Av. Manuel Nava 6, Zona Universitaria, SLP 78290, San Luis Potosi, Mexico

^* e-mail: mauro@fisica.ugto.mx

Received: 15 October 2005
Accepted: 1 September 2006
Published online: 20 September 2006

Abstract

We employ the two independent Casimir operators of the Poincaré group, the squared four-momentum, p², and the squared Pauli-Lubanski vector, W², in the construction of a covariant mass m, and spin- projector in the four-vector spinor, ψ_μ. This projector provides the basis for the construction of an interacting Lagrangian that describes a causally propagating spin- particle coupled to the electromagnetic field by a gyromagnetic ratio of .