Theory of deep inelastic neutron scattering on quantum fluids

The line shape for high-momentum-transfer neutron scattering experiments on quantum fluids is derived by a novel perturbative method which includes the effect of the spatial correlations in the ground state. The final-state broadening of the impulse approximation is shown to be non-Lorentzian, to have a zero second moment, and to be significant for all feasible experiments. There are important implications for the goal of measuring momentum distributions. Numerical results are presented for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$.