Compton amplitude for massive bosons of arbitrary spin

In this work, we write down an analytic expression of electromagnetic tree-level Compton amplitude for a completely symmetric traceless (bosonic) higher spin particle in any dimension. Our analysis is restricted to the three-point function, which is unique in the Infrared and responsible for the Coulomb interactions/soft photon theorem. We propose an analogue of $R_\xi$ gauge in a theory of higher spin particles. We demonstrate that the theory is unitary only for $\xi=1,\infty$.