Systematics of Higher-spin Light-front Interactions

Understand

The original cubic interaction terms for higher spin gauge fields in four dimensions and their reformulation using Fock space vertex operators is reviewed.

• As a new result, the complete list of all cubic vertex functions in D=4 is derived.
• It is observed, contrary to what would have been expected, that the non-linear dynamical Poincar\'e transformations do not restrict the cubic interactions beyond what is required by kinematics.
• The role of the SU(1,1) algebra of tracelessness constraints is clarified.