Ghost and tachyon free propagation up to spin 3 in Lorentz invariant field theories

Abstract

We complete the set of spin-projector operators for fields up to rank 3 by providing all operators connecting sectors with the same spin and parity. In this way, we can broaden the search for unitary and nontachyonic particle propagation in quadratic Lagrangians with interfield mixing. We use the properties of projector algebra to reanalyze known theories and shed light on new, healthy ones. We do so with full control over the gauge constraints by determining the form of the saturated propagator in an appropriate frame of reference.

Topics & Concepts