  We study different patterns of interference in WIMP-nuclei elastic scattering
that can accommodate the DAMA and CoGeNT experiments via an isospin violating
ratio $f_n/f_p=-0.71$. We study interference between the following pairs of
mediators: Z and Z', Z' and Higgs, and two Higgs fields. We show under what
conditions interference works. We also demonstrate that in the case of the two
Higgs interference, an explanation of the DAMA/CoGeNT is consistent with
Electroweak Baryogenesis scenarios based on two Higgs doublet models proposed
in the past.
