  We calculate the single-particle spectral functions and quasi-particle
dispersions for a Bose-Fermi mixture when the boson-fermion attraction is
sufficiently strong to suppress completely the condensation of bosons at zero
temperature. Within a T-matrix diagrammatic approach, we vary the boson-fermion
attraction from the critical value where the boson condensate first disappears
to the strongly attractive (molecular) regime and study the effect of both
mass- and density-imbalance on the spectral weights and dispersions. An
interesting spectrum of particle-hole excitations mixing two different Fermi
surfaces is found. These unconventional excitations could be produced and
explored experimentally with radio-frequency spectroscopy.
