High-momentum excitations in liquid He4

The dynamic structure factor of liquid He4 is calculated on the basis of four moments. One of the functions, which corresponds to the centre of main distribution observed by the neutron scattering method, exhibits oscillatory deviations from the energy of free helium atoms. These oscillations have been found to be in good agreement with the experimental data of Cowley and Woods. The width of the same distribution, approximated by the Gaussian form, is also estimated and general agreement is established. (author)