  We theoretically study the relaxation of high energy single particle
excitations into molecules in a system of attractive fermions in an optical
lattice, both in the superfluid and the normal phase. In a system characterized
by an interaction scale $U$ and a tunneling rate $t$, we show that the
relaxation rate scales as $\sim Ct\exp(-\alpha U^2/t^2)$ in the large $U/t$
limit. We obtain explicit expressions for the exponent $\alpha$, both in the
low temperature superfluid phase and the high temperature phase with pairing
but no coherence between the molecules. We find that the relaxation rate
decreases both with temperature and deviation of the fermion density from
half-filling. We show that quasiparticle and phase degrees of freedom are
effectively decoupled within experimental timescales allowing for observation
of ordered states even at high total energy of the system.
