A. Sharma et al., MASS AND SPIN CONTENT OF A FREE RELATIVISTIC PARTICLE OF ARBITRARY SPILL AND THE GROUP REDUCTION SP(4)SUPERSET-OF-U(1)CIRCLE-TIMES-SU(2), Revista mexicana de fisica, 44, 1998, pp. 23-25
In this paper, we apply Foldy-Wouthuysen transformations to the relati
vistic equation for a free particle of arbitrary spin, which has the s
ymmetry group O(5) associated with it. By noting the isomorphism of O(
5) to the symplectic group Sp(4), the mass and spin content of the pro
blem is found using the group reduction Sp(4) superset of U(1) x SU(2)
where U(1) is associated with the masses while SU(2) is related to th
e spins.