  A Dynamical Mean Field Theory analysis of the attractive Hubbard model is
carried out. We focus on the normal state upon restricting to solutions where
superconducting order is not allowed. Nevertheless a clear first-order pairing
transition as a function of the coupling takes place at all the electron
densities out of half-filling. The transition occurs between a Fermi liquid,
stable for $U < U_c$, and an insulating bound pairs phase for $U > U_c$. The
spectral function in the Fermi liquid phase is constituted by a low energy
structure around the Fermi level (similar to the Kondo resonance of the
repulsive half-filled model), which disappears discontinuously at $U=U_c$, and
two high energy features (lower and upper Hubbard bands), which persist in the
insulating phase.
