Absolute Continuity of Measure Branching Processes with Interaction

We study the state properties of the measure branchiug process over IR with mean field interaction coustructed by Meleard and Roelly （1992, 1993） and Metivier （1987）. It is proved that, under natural hypotheses, the process is absolutely continuous with respect to the Lebesgue measure and the density process has a continuous version which satisfies a stochastic partial differential equation.