  We find Marginal Fermi Liquid (MFL) like behavior in the Hubbard model on a
square lattice for a range of hole doping and on-site interaction parameter U.
Thereby we use a self-consistent projection operator method. It enables us to
compute the momentum and frequency dependence of the single-particle
excitations with high resolution. The Fermi surface is found to be hole-like in
the underdoped and electron-like in the overdoped regime. When a comparison is
possible we find consistency with finite temperature quantum Monte Carlo
results. We also find a discontinuous change with doping concentration from a
MFL to Fermi liquid behavior resulting from a collapse of the lower Hubbard
band. This renders Luttinger's theorem inapplicable in the underdoped regime.
