D=4 supergravity dynamically coupled to a massless superparticle in a superfield Lagrangian approach

We consider the interacting system of D=4 N=1 supergravity and the Brink-Schwarz massless superparticle as described by the sum of their superfield actions, and derive the complete set of superfield equations of motion for the coupled dynamical system. These include source terms given by derivatives of a vector superfield current density with support on the worldline. This current density is constructed from the spin 3/2 and spin 2 current density `prepotentials'. We analyze the gauge symmetry of the coupled action and show that it is possible to fix the gauge in such a way that the equations of motion reduce to those of the supergravity-bosonic particle coupled system.