Spin-(5/2) fields in hadron physics
We show that the Lagrangian of a free spin-(5/2) field in the spinor-tensor representation with an auxiliary spinor field depends on three arbitrary parameters. The first two parameters are associated with the spin-(3/2) and spin-(1/2) sector of the theory while the last is related to the auxiliary degrees of freedom. We derive a corresponding propagator of the system which represents a (2x2) matrix in the (psi{sub m}u{sub n}u,xi) space. The diagonal terms stand for the propagation of the spin-(5/2) and auxiliary fields whereas the nondiagonal ones correspond to the psi{sub m}u{sub n}u-xi mixing. The resulting spin-(5/2) propagator contains nonpole contributions coming from the spin-(3/2) and spin-(1/2) sector of the spinor-tensor representation. A general form of the interaction vertex involving the spin-(5/2) field is discussed by the example of the piNN{sub (5/2)}* coupling. It is demonstrated that lower spin degrees of freedom can be removed from the theory by use of higher-order derivative coupling.