The Simplest Dark-Matter Model, CDMS II Results, and Higgs Detection at
  LHC
  The direct-search experiment for dark matter performed by the CDMS II
Collaboration has observed two candidate events. Although these events cannot
be interpreted as significant evidence for the presence of weakly interacting
massive particle (WIMP) dark matter (DM), the total CDMS II data have led to an
improved upper-limit on the WIMP-nucleon spin-independent cross-section. We
study some implications of these results for the simplest WIMP DM model, the
SM+D, which extends the standard model (SM) by the addition of a real
SM-singlet scalar field dubbed darkon to play the role of the DM. We find that,
although the CDMS II data rule out a sizable portion of parameter space of the
model, a large part of the parameter space is still allowed. We obtain strong
correlations among the darkon mass, darkon-nucleon cross-section, mass of the
Higgs boson, and branching ratio of its invisible decay. We point out that
measurements of the Higgs invisible branching-ratio at the LHC can lift some
possible ambiguities in determining the darkon mass from direct DM searches.
