  We consider a class of interacting particle systems with values in
$[0,\8)^{\zd}$, of which the binary contact path process is an example. For $d
\ge 3$ and under a certain square integrability condition on the total number
of the particles, we prove a central limit theorem for the density of the
particles, together with upper bounds for the density of the most populated
site and the replica overlap.
