Why We Exist: Matter Wins Battle Over Antimatter
20 May 2010
Why We Exist...
Welcome to my world. Enjoy!
The seemingly inescapable
fact that matter and antimatter
particles destroy each other on contact has
long puzzled physicists wondering how life, the universe or anything
else can
exist at all. But new results from a particle accelerator experiment suggest
that matter does seem to win in the end.
The experiment has shown a
small — but significant — 1 percent difference between the amount of matter
and antimatter produced, which could hint at how our
matter-dominated existence
came about.
The current theory, known
as the Standard Model
of particle physics,
has predicted some violation of
matter-antimatter symmetry, but not enough to explain how our universe
arose
consisting mostly of matter with barely a trace of antimatter.
But this latest experiment
came up with an unbalanced ratio of matter to antimatter that goes
beyond the
imbalance predicted by the Standard Model. Specifically, physicists
discovered
a 1 percent difference between pairs of muons and antimuons that arise
from the
decay of particles known as B mesons.
The results, announced
Tuesday, came from analyzing eight years worth of data from the Tevatron
collider at the Department
of Energy's Fermi National Accelerator Laboratory in
Batavia, Ill.
"Many of us felt goose
bumps when we saw the result," said Stefan Soldner-Rembold, a particle
physicist at the University of Manchester in the United Kingdom. "We
knew
we were seeing something beyond what we have seen before and beyond what
current theories can explain."
The Tevatron collider and
its bigger cousin, the Large Hadron Collider
at CERN in Switzerland, can smash matter and
antimatter particles together to create energy, as well as new particles
and
antiparticles. Otherwise, antiparticles only arise due to extreme events
such as
nuclear reactions
or cosmic rays from
dying stars.
Measurements made by the
DZero collaboration, a 500-member international group, are still limited
by the
number of collisions recorded so far. That means physicists will
continue to
collect data and refine their analysis of the matter-antimatter struggle
for
dominance.
Researchers came up with
their latest finding by performing a so-called blind data analysis, so
that
they would not bias their analyses based on what they observed. They
have submitted
their results to the journal Physical Review D.
17 May 2010
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