Beyond the binary collision approximation for the large-$q$ response of liquid ${}^4$He

Abstract

We discuss corrections to the linear response of a many-body system beyond the binary collision approximation. We first derive for smooth pair interactions an exact expression of the response $\propto 1/q^2$, considerably simplifying existing forms and present also the generalization for interactions with a strong, short-range repulsion. We then apply the latter to the case of liquid ${}^4$He. We display the numerical influence of the $1/q^2$ correction around the quasi-elastic peak and in the low-intensity wings of the response, far from that peak. Finally we resolve an apparent contradiction in previous discussions around the fourth order cumulant expansion coefficient. Our results prove that the large-$q$ response of liquid ${}^4$He can be accurately understood on the basis of a dynamical theory.

19 p. Figs. available on request

References in corpus (1)

• Description of recent large-$q$ neutron inclusive scattering data from liquid ${}^4$He

Cited by in corpus (3)

• Theoretical aspects of the CEBAF 89-009 experiment on inclusive scattering of 4.05 GeV electrons from nuclei
• On the equivalence of the Impulse Approximation and the Gersch-Rodriguez-Smith theory for structure functions
• Extraction of nucleon momentum distributions from inclusive electron scattering on nuclei