  A family of diffusion-annihilation processes is introduced, which is exactly
solvable. This family contains parameters that control the diffusion- and
annihilation- rates. The solution is based on the Bethe ansatz and using
special boundary conditions to represent the reaction. The processes are
investigated, both on the lattice and on the continuum. Special cases of this
family of processes are the simple exclusion process and the drop-push model.
