The hybridization of the single-excitation branch with the two-excitation continuum is reconsidered from the theoretical point of view by including the effect of the interference term between one and two excitations. The phe-nomenological model presented is used to reproduce the experimental data over a wide region of momentum (2.3-3.6 Å−1) and energy (0-12 meV). The model thus allows to extract the final part of 4He spectrum with higher accuracy. It is found that data agree with a dispersion relation always below twice the roton energy. This is consistent with the negative value of the roton-roton interaction found.