Higgs Boson

"Higgsogenesis" Proposed to Explain Dark
Matter

Interactions of Higgs bosons and anti-Higgs in the
early universe may also have caused the observed
asymmetry between matter and antimatter
By Eugenie Samuel Reich and Nature magazine
The Higgs boson may have played a key role in
the early Universe, including the creation of
mysterious dark matter.

A key riddle in cosmology may be answered by the
2012 discovery of the Higgs boson—now a leading
contender for the 2013 Nobel Prize in Physics on
October 8.

 

Two physicists suggest that the Higgs had a key role
in the early universe, producing the observed
difference between the number of matter and
antimatter particles and determining the density of
the mysterious dark matter that makes up five-
sixths of the matter in the universe.
In a paper accepted for publication in Physical
Review Letters, Sean Tulin of the University of
Michigan in Ann Arbor and Géraldine Servant of the
Catalan Institute for Research and Advanced Study
in Barcelona, Spain, say that there may have been
an asymmetry in the early universe between the
Higgs boson and its antimatter counterpart, the anti-
Higgs.

It is thought that the Higgs does not currently have
an antiparticle, but the standard cosmological model
allows for there to have been both Higgs bosons and
anti-Higgs bosons in the very early universe. Tulin
and Servant’s idea is that there was an imbalance
between the numbers of these particles. The Higgs
interacts with ordinary matter, and that imbalance
in the number of Higgs and anti-Higgs particles
could have translated into an asymmetry in the
amount of matter and antimatter.“We really make
the Higgs a key player, whereas in many other
cosmological theories it's just a by-product,” says
Tulin.

The team has dubbed the idea Higgsogenesis, after
baryogenesis, the name of an early-universe process
that has been proposed to create more baryons
(particles including protons and neutrons) than
antibaryons. “Higgsogenesis is an alternative,” says
Tulin.

Missing particles
Tulin and Servant show that if the Higgs also
interacted with dark matter—for example by
generating dark-matter particles when it decays—it
could produce a ratio of dark to visible matter that
is just what we see in the universe today. Servant
says that one consequence of the Higgs interacting
in this way would be a new potential test for dark
matter, which has so far proven difficult to see
directly. When the Higgs decays to other particles in
the Large Hadron Collider at CERN, Europe's
particle-physics laboratory near Geneva,
Switzerland, it would occasionally form dark-matter
particles that could not be detected. Higgs decays at
the LHC have not yet been studied closely enough to
tell whether this is happening, but could be in
future, Servant says.

Other groups are also pursuing Higgsogenesis. In
July, theorist Sacha Davidson of the University of
Lyons in France and her colleagues uploaded a
paper to the preprint server arXiv investigating
what would be required to produce the asymmetry
between the Higgs and anti-Higgs that would kick
off Higgsogenesis in the early universe. They found
that a relatively simple theory—in which the
standard model of particle physics includes all the
normal particles, as well as two Higgs and one extra,
unobservable Higgs-like particle—can produce an
asymmetry of the type that Servant and Tulin
propose.

Manoj Kaplinghat, a theoretical physicist at the
University of California, Irvine, likes Tulin and
Servant’s proposal because of its simplicity. “We
know that the Higgs exists, we know there’s dark
matter and matter–antimatter asymmetry, and
they’re trying to put three empirical facts together,”
he says. “It's a minimal approach and that makes it
interesting.”

This article is reproduced with permission from the
magazine Nature . The article was first published on
October 4, 2013.

Source: http://www.scientificamerican.com/article.cfm?id=higgsogenesis-proposed-to-explain-dark-matter