  The hybridization of the single-excitation branch with the two-excitation
continuum in the momentum region beyond the roton minimum is reconsidered by
including the effect of the interference term between one and two excitations.
Fits to the latest experimental data with our model allow us to extract with
improved accuracy the high momentum end of the $^4$He dispersion relation. In
contrast with previous results we find that the undamped excitations below two
times the roton energy survive up to Q=3.6 A^{-1} due to the attractive
interaction between rotons.
