The CoGeNT collaboration has reported evidence of an annual modulation in its
first fifteen months of data. Here we compare the amplitude and phase of this
signal to the modulation observed by the DAMA collaboration, assuming that both
arise due to elastically scattering dark matter (DM). We directly map the
CoGeNT signal to the DAMA detector without specifying any astrophysical
parameters and compare this with the signal measured by DAMA. We also compare
with constraints from CDMS II and XENON10. We find that DM of mass 5-14 GeV
that couples equally to protons and neutrons is strongly disfavoured.
Isospin-violating DM fares better but requires a boosted modulation fraction.Comment: 6 pages, 3 figures. v2 Refs updated, typos corrected and Section V
updated to include discussion of CDMS II-Si and XENON1