Tensor approach to spin-one mesons. III. Magnetic dipole moment and electric quadrupole moment

In previous papers the massive spin-one mesons were described by means of an antisymmetric second-rank tensor field. In the present paper their free Lagrangian is modified in such a way that when the electromagnetic interactions are introduced by the minimal substitution the mesons get an arbitrary magnetic dipole moment. The addition of other terms in the Lagrangian allows the spin-one mesons to also have an arbitrary electric quadrupole moment. The covariance of the $S$ matrix to order ${e}^{2}$ is achieved by the addition of counterterms.