  Liquid Xenon (LXe) is expected to be an excellent target and detector medium
to search for dark matter in the form of Weakly Interacting Massive Particles
(WIMPs). Knowledge of LXe ionization and scintillation response to low energy
nuclear recoils expected from the scattering of WIMPs by Xe nuclei is important
for determining the sensitivity of LXe direct detection experiments. Here we
report on new measurements of the scintillation yield of Xe recoils with
kinetic energy as low as 10 keV. The dependence of the scintillation yield on
applied electric field was also measured in the range of 0 to 4 kV/cm. Results
are in good agreement with recent theoretical predictions that take into
account the effect of biexcitonic collisions in addition to the nuclear
quenching effect.
