  We study the limiting behavior of an interacting particle system evolving on
the lattice $Z^{d}$ for $d\ge 3$. The model is known as the contact process
with rapid stirring. The process starts with a single particle at the origin.
Each particle may die, jump to a neighboring site if it is vacant or split. In
the case of splitting, one of the offspring takes the place of the parent while
the other, the newborn particle, is sent to another site in $Z^{d}$ according
to a certain distribution; if the newborn particle lands on an occupied site,
its birth is suppressed. We study the asymptotic behavior of the critical
branching rate as the jumping rate (also known as the stirring rate) approaches
infinity.
