Is cold dark matter made of Higgs bosons?

This paper (2010) hypothesizes that Higgs bosons might be absolutely stable, allowing them to serve as a cold dark matter candidate:

The Higgs boson is in the backbone of the standard model of electroweak interactions. It must exist in some form for achieving unification of interactions. In the gauge-Higgs unification scenario the Higgs boson becomes a part of the extra-dimensional component of gauge fields. The Higgs boson becomes absolutely stable in a class of the gauge-Higgs unification models, serving as a promising candidate for cold dark matter in the universe. The observed relic abundance of cold dark matter is obtained with the Higgs mass around 70 GeV. The Higgs-nucleon scattering cross section is found to be close to the recent CDMS II and XENON10 bounds in the direct detection of dark matter. In collider experiments stable Higgs bosons are produced in a pair, appearing as missing energies and momenta so that the way of detecting Higgs bosons must be altered.

–"Stable Higgs Bosons - new candidate for cold dark matter", Yutaka Hosotani (2010-03-31)

Has the hypothesis in the above article been proved? What about WIMPs?

Answer

Dark Matter candidates have to interact very weakly with the particles of the Standard Model in order to have a relic density compatible with the one measured by the Plank satellite. The Higgs boson cannot be Dark Matter, because the decay rate for a process like $H\to f\bar{f}$ is very high for a mass around $m_\text{H}=126 ~\rm{GeV}$.

However, there are still some very interesting possibilities concerning scalar particles. If we want to have the correct relic density without considering extremely heavy dark matter particles, then we have to suppose the existence of a mediator that makes the connections between the Standard Model and the "Dark Sector".

Two possibilities are:

1. a very light vector boson, so-called "dark photon" (0607094),


2. a light pseudoscalar boson (0712.0016).

In particular, in most extension of the SM there are several "Higgs bosons" and maybe one of these particles can be such a mediator. Two particular examples are the Minimal Supersymmetric Standard Model (MSSM) and the Next-to-Minimal Supersymmetric Standard Model (NMSSM). In the latter case, it is possible to have a very light CP-odd particle (pseudoscalar) in addition to the Higgs boson observed at the LHC. Usually the latter is identified with the lightest CP-even boson of these models (cf. 1301.1325).

In conclusion, we know very little about dark matter and its interaction, but the possibility of having a new Higgs boson that could explain the experimental results like the CMB measurements is not completely ruled out.