A classical theory of continuous spin and hidden gauge invariance

We present a classical higher derivative point particle theory whose quantization gives Wigner's continuous spin representation of the Poincaré group. Although the theory is not reparametrization-invariant in the usual sense, it does possess a hidden gauge invariance that provides a non-local representation of the reparametrization group. The Hamiltonian of the theory does not vanish and its value is the continuous spin parameter. The theory presented here represents the simples example of a wide class of higher derivative theories possessing a hidden gauge invariance.