A partially broken Fronsdal model for massless higher-spin particles of integer spin

A bstract By introducing arbitrary parameters in the usual Fronsdal model, we find a region in the parameters space away from the “Fronsdal point” where we still have an irreducible description of massless particles of arbitrary integer spin s ≥ 3. The higher spin gauge symmetry is further constrained by a vanishing double divergence condition on the traceless gauge parameter: $$\partial \cdot \partial \cdot \stackrel{\text{-}}{\Lambda}=0$$ . Remarkably, it does not introduce extra propagating gauge invariants. We demonstrate that we only have spin- s helicity states as propagating modes for arbitrary integer s ≥ 3. For the simplest s = 3 case we present a gauge invariant proof while for s ≥ 4 we use a light-cone gauge. The reduction in the gauge symmetry allows for more general source couplings when compared to the Fronsdal model.