Deviations from the impulse approximation in liquid sup 4 He: An experimental test at Q =23 A sup minus 1

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.216· OSTI ID:5989258

Sosnick, T R; Snow, W M ^[1]; Silver, R N ^[2]; Sokol, P E ^[3]

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1. Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, IL (USA)
2. Theoretical Division and Los Alamos Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, NM (USA)
3. Department of Physics, The Pennsylvania State University, University Park, PA (USA)

Deep-inelastic-scattering measurements at high-momentum transfer {ital Q} can provide direct information on the momentum distribution of a system of particles if the impulse approximation (IA) is valid. In many such experiments, however, deviations between the observed scattering and predictions based on the IA are present. In liquid {sup 4}He these deviations, called final-state effects (FSE), are caused by interactions among the particles. We have used liquid {sup 4}He as a testing ground for the study of FSE. Deep-inelastic-neutron-scattering measurements on liquid {sup 4}He have been carried out for temperatures of 0.35 and 3.5 K at a density of 0.147 g/cm{sup 3}. Under the assumption that current theoretical calculations of the momentum distribution of liquid {sup 4}He are accurate, we extract the form of FSE in the superfluid phase from the scattering data. We also compare the predictions of several theories for FSE to the experimental data. At the momentum transfer of {ital Q}=23 A{sup {minus}1} reached in these measurements, we find that an FSE theory due to Silver is the only current theory in agreement with the data in both the normal and superfluid phases.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5989258
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:1; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COHERENT SCATTERING
DEEP INELASTIC SCATTERING
DIFFRACTION
DISPERSION RELATIONS
ELEMENTS
FLUIDS
GASES
HELIUM
IMPULSE APPROXIMATION
INELASTIC SCATTERING
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MOMENTUM TRANSFER
NEUTRON DIFFRACTION
NONMETALS
PARTICLE INTERACTIONS
RARE GASES
SCALING LAWS
SCATTERING
STRUCTURE FACTORS
SUPERFLUIDITY
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE