Interacting massive and massless arbitrary spin fields in 4d flat space

TL;DR

This paper develops a formalism for analyzing cubic interactions between massive and massless arbitrary spin fields in 4D flat space, providing a classification and explicit construction of interaction vertices.

Contribution

It introduces a novel classification scheme for cubic interactions and constructs all such vertices using a light-cone gauge helicity basis formalism.

Findings

Classification of cubic interactions between massive and massless fields.

Explicit construction of all cubic interaction vertices.

Realization of Poincare algebra generators on interacting fields.

Abstract

Massive and massless arbitrary integer spin fields propagating in four-dimensional flat space are studied. The massive and massless fields are treated by using a light-cone gauge helicity basis formalism. Cubic cross-interactions between massive and massless fields and cubic interactions between massive fields are investigated. We introduce a classification of such cubic interactions and using our classification we build all cubic interaction vertices. Realization of generators of the Poincare algebra on space of interacting fields is found. As a by-product, some illustrative examples of light-cone form for 3-point invariant amplitudes of massive and massless fields are also discussed.