[en] We present a new approach for studying the energy spectrum of superfluid Helium 4. It is based on the assumption that there exist localized modes in addition to the usual Feynman density fluctuations (phonons). They correspond to the short range behaviour in the liquid where effects of quantum statistics are important. We describe in a phenomenological way the hybridization of those two kinds of excitations and we compare the resulting energy spectrum with experimental results, e.g. the structure factor and the single excitation scattering intensity. We also predict the existence of another type of excitation interpreted as a vortex loop. The energy of this mode agrees both with the Raman scattering data and critical velocity experiments of Varoquaux et al.