  This paper considers the decay in particle intensities for a translation
invariant two species system of diffusing and reacting particles on
$\mathbb{Z}^d$ for $d \geq 3$. The intensities are shown to approximately solve
modified rate equations, from which their polynomial decay can be deduced. The
system illustrates that the underlying diffusion and reaction rates can
influence the exact polynomial decay rates, despite the system evolving in a
supercritical dimension.
