Isospin-violating dark-matter-nucleon scattering via
  two-Higgs-doublet-model portals
  We show that in a multi-Higgs model in which one Higgs fits the LHC 125 GeV
state, one or more of the other Higgs bosons can mediate DM-nucleon
interactions with maximal DM isospin violation being possible for appropriate
Higgs-quark couplings, independent of the nature of DM. We then consider the
explicit example of a Type II two-Higgs-doublet model, identifying the h or H
as the 125 GeV state while the H or h, respectively, mediates DM-nucleon
interactions. Finally, we show that if a stable scalar, S, is added then it can
be a viable light DM candidate with correct relic density while obeying all
direct and indirect detection limits.
