UCLA Physicists Offer a
Solution
to the Puzzle of the Origin
of Matter
in the Universe
By Stuart Wolpert, UCLA Newsroom, February 24, 2015
Most of the laws of nature treat particles and antiparticles
equally, but stars and planets are made of particles, or matter, and not
antiparticles, or antimatter. That asymmetry, which favors matter to a very
small degree, has puzzled scientists for many years.
New research by UCLA physicists, published in the journal
Physical Review Letters, offers a possible solution to the mystery of the
origin of matter in the universe.
Alexander Kusenko, a professor of physics and astronomy in
the UCLA College ,
and colleagues propose that the matter-antimatter asymmetry could be related to
the Higgs boson particle, which was the subject of prominent news coverage when
it was discovered at Switzerland
Specifically, the UCLA researchers write, the asymmetry may
have been produced as a result of the motion of the Higgs field, which is
associated with the Higgs boson, and which could have made the masses of
particles and antiparticles in the universe temporarily unequal, allowing for a
small excess of matter particles over antiparticles.
If a particle and an antiparticle meet, they disappear by emitting
two photons or a pair of some other particles. In the “primordial soup” that
existed after the Big Bang, there were almost equal amounts of particles of
antiparticles, except for a tiny asymmetry: one particle per 10 billion. As the
universe cooled, the particles and antiparticles annihilated each other in
equal numbers, and only a tiny number of particles remained; this tiny amount
is all the stars and planets, and gas in today’s universe, said Kusenko, who is
also a senior scientist with the Kavli Institute for the Physics and
Mathematics of the Universe.
The research also is highlighted by Physical Review Letters
in a commentary in the current issue.
The 2012 discovery of the Higgs boson particle was hailed as
one of the great scientific accomplishments of recent decades. The Higgs boson
was first postulated some 50 years ago as a crucial element of the modern
theory of the forces of nature, and is, physicists say, what gives everything
in the universe mass. Physicists at the LHC measured the particle’s mass and
found its value to be peculiar; it is consistent with the possibility that the
Higgs field in the first moments of the Big Bang was much larger than its
“equilibrium value” observed today.
The Higgs field “had to descend to the equilibrium, in a
process of ‘Higgs relaxation,’” said Kusenko, the lead author of the UCLA
research.
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