Implications of CoGeNT's New Results For Dark Matter
  The CoGeNT collaboration has recently presented the results of their first 15
months of data, including the measurement of the spectrum of nuclear recoil
candidate events, and the time variation of those events. These results appear
consistent with the signal anticipated from a relatively light dark matter
particle scattering elastically with nuclei. In this paper, we independently
analyze the data set collected by CoGeNT and explore the implications of these
results for dark matter. We find that the observed spectrum and rate is
consistent with originating from dark matter particles with a mass in the range
of 4.5-12 GeV and an elastic scattering cross section with nucleons of
approximately ~10^-40 cm^2. We confirm the conclusion of the CoGeNT
collaboration that the data also includes a somewhat statistically significant
(2.7 sigma) indication of annual modulation, with a phase, period, and
amplitude consistent with that predicted for dark matter. CoGeNT's phase is
also consistent with the annual modulation reported by the DAMA/LIBRA
collaboration. We also discuss the null results reported by CDMS and XENON100,
and comment on the prospects for other experiments to detect a dark matter
particle with the properties implied by CoGeNT.
