Temperature Dependence of Spin-Density Fluctuations in Liquid 3He

The dynamic structure factor S(Q,E) in normal liquid³He, which contains information on both density and spin-density fluctuations, has been measured by inelastic neutron scattering both well below and close to the Fermi temperature. The data extend to smaller wave vectors and energies than covered in earlier experiments, and give a much better determination of the line shape of the spin-density response. Together with the temperature dependence, this allows to discriminate between different theoretical models for the nuclear spin fluctuations, and provides information on the quasiparticle dispersion and effective mass.