XENON10/100 dark matter constraints in comparison with CoGeNT and DAMA:
  examining the Leff dependence
  We consider the compatibility of DAMA/LIBRA, CoGeNT, XENON10 and XENON100
results for spin-independent (SI) dark matter Weakly Interacting Massive
Particles (WIMPs), particularly at low masses (~ 10 GeV), assuming a standard
dark matter halo. The XENON bounds depend on the scintillation efficiency
factor Leff for which there is considerable uncertainty. Thus we consider
various extrapolations for Leff at low energy. With the Leff measurements we
consider, XENON100 results are found to be insensitive to the low energy
extrapolation. We find the strongest bounds are from XENON10, rather than
XENON100, due to the lower energy threshold. For reasonable choices of Leff and
for the case of SI elastic scattering, XENON10 is incompatible with the
DAMA/LIBRA 3$\sigma$ region and severely constrains the 7-12 GeV WIMP mass
region of interest published by the CoGeNT collaboration.
