Two-field local action for a free massless integer spin-s particle that removes the trace constraints of the Fronsdal formulation: a rank-s symmetric field phi paired with a single rank-(s-3) Stueckelberg compensator alpha, with the usual rank-(s-4) Lagrange multiplier traded for a Weyl-like gauge symmetry so the theory is invariant under fully unconstrained (traceful) higher-spin diffeomorphisms. Covers how the model reproduces the tensionless-limit equations of open bosonic string field theory truncated to pure spin-s modes, and the explicit s=4 case where integrating out alpha yields a nonlocal Weyl-plus-Diff invariant action whose spin-4 propagator, analyzed with a complete basis of nonlocal projection and transition operators, propagates only the massless spin-4 polarizations.
This paper proposes a new local action for free massless particles of arbitrary integer spin s built from only two symmetric fields: the rank-s physical field phi and a rank-(s-3) Stueckelberg-like f…