[Physics] Higgs boson and dark matter.

dark-matterhiggsparticle-physics

In the standard model the Higgs boson gives the mass to other particles, but in the Universe we know that the 80% of mass is in form of dark matter, that is not constituted by known particles. The Higgs boson gives the mass also to the dark matter with the same mechanism?

Best Answer

The question is whether dark matter gets its mass from the Higgs field. The answer depends on the composition of dark matter, so let's discuss the mass explanations for several common composition hypotheses in turn. (We needn't discuss alternatives to dark matter, such as MOND or gravity no longer obeying an inverse square law over kiloparsecs.)

If dark matter is neutrinos, blame the seesaw mechanism. (However, as a comment below notes, this hypothesis hasn't aged well.)

If dark matter is composed of MACHOs - in short, a particular kind of star or former star - almost all the mass comes from baryons (particles such as protons and neutrons), and almost all of their mass comes from the potential energy of the strong force holding the quarks together in baryons. This is why, although the Higgs field gives the quarks in protons some mass, the proton mass is dozens of times what would be expected from that alone.

Finally, if dark matter is composed of the lightest "supersymmetric partner", the Higgs field is responsible. One motivation for postulating supersymmetric partners much more massive than familiar particles is that it allows us to reduce quadratic divergences in the Higgs field to logarithmic divergences. One version of this theory conserves a multiplicative charge called R-parity, which is $1$ for known particles but $-1$ for their supersymmetry partners. The lightest such partner therefore cannot decay, even if its Higgs-induced mass is very large.

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