  We study numerically the interaction and disorder effects for two
quasiparticles in two and three dimensions. The dependence of the
interaction-induced Breit-Wigner width on the excitation energy above the Fermi
level, the disorder strength and the system size is determined. A regime is
found where the width is practically independent of the excitation energy. The
results allow to estimate the two quasiparticle mobility edge.
