After all these years, they have
finally developed a protocol that collects and stores anti matter in the form
of anti hydrogen and did so in enough quantity to envision the possibility of
doing direct experiments.
Obviously we can go beyond this
and plausibly see our way to producing working quantities of this stuff,
although serious production will need to be conducted in space. One really can not get serious otherwise about
a product that will really ruin your day every time there is an accident.
In the meantime, this allows real
work to begin in the labs.
pp
pp
Antimatter atoms trapped for 16 minutes
By Emily Chung, CBC
News
Posted: Jun 6, 2011 11:40 AM ET
Some of the researchers involved in the discovery are from Canada,
including, from left to right, Michael Hayden and Mohammad Ashkezari from Simon
Fraser University; Tim Friesen from the University of Calgary; Makoto Fujiwara
from TRIUMF; and Andrea Gutierrez and Walter Hardy from the University of
British Columbia. They are shown with their experimental setup at the CERN
Laboratory near Geneva
Antimatter atoms have been held captive and kept in existence for a
whopping 16 minutes by a Canadian-led team — far longer than the researchers
thought possible.
"It was quite a surprise," said Makoto Fujiwara, lead author
of a study published Sunday in Nature Physics. It reported trapping antiatoms
of antihydrogen — the antimatter counterpart of a hydrogen atom — for 1,000
seconds.
Antimatter is made up of "antiparticles" that have the same
mass as corresponding particles of matter, but an opposite charge. For example,
the antimatter counterpart of a negatively charged electron is a positively
charged positron.
Antimatter is very difficult to keep in existence because the moment it
touches matter, which makes up most of our universe, both the matter and
antimatter are annihilated, producing pure energy.
The scientists' recent achievement has extended the experimental
lifetime of antihydrogen atoms 5,000-fold since the ALPHA experiment — an
international collaboration Fujiwara is part of — first figured out how to trap
them at all.
The team, based at the laboratory of CERN, the European organization
for nuclear research, near Geneva
Holding antiatoms captive for several minutes opens up a new range of
possible experiments to probe the nature of antimatter, said Fujiwara, a
research scientist at Vancouver-based TRIUMF and an adjunct professor at the University of Calgary
'Game changer'
Scientists will more easily be able to do experiments to compare
antihydrogen to hydrogen and could even potentially test how antimatter atoms
are affected by gravity, he added. "I call it a game changer."
An antihydrogen atom is released from the trap after 1,000 seconds, in
an artist's conception. The squiggly line represents the atom's path in the
trap while it is trapped, and the curved tracks emerging represent the energy
produced when the released anti-atom hits the inner wall of the trap.CERN/ALPHA
Antihydrogen is made by mixing antiparticles called antiprotons (the
antimatter counterparts of protons) and positrons (the antimatter counterparts
of electrons). In recent months, Fujiwara said, the ALPHA team has figured out
how to create very cold antiparticles and mix them more gently to produce and
trap antiatoms more efficiently, successfully trapping an average of one
antiatom per trial.
They also decided to test how long they could keep the antiatoms
trapped. Fujiwara thought holding on to them for several seconds might be
possible and was stunned that they could survive for many minutes.
That will make it much easier to do experiments to compare antihydrogen
to hydrogen, he added.
For example, researchers can point lasers and microwaves at the
antiatoms and figure out how the colours of light they shine back compare to
those shone back by hydrogen atoms under the same circumstances, Fujiwara said.
Aiming the lasers and microwaves precisely at the antiatoms using the
right settings is very difficult right after the antiatoms are formed because
they are in what's called an excited state — the positrons are orbiting the
nucleus of the antiatom, but they're very far away, and they're constantly
changing their orbit.
Over time, they reach a stable orbit close to the nucleus known as the
"ground state." That allows the lasers and microwaves to be aimed
with high precision. Theoretical calculations show that after several minutes,
the antiatoms should all be in the ground state.
Studying the effect of gravity on antimatter is particularly
challenging because gravity acts so weakly compared to other forces on
particles with such a tiny mass, so a lot of time is needed.
"The possibility of studying gravitational effects really become
feasible now," Fujiwara said. "That’s something I’m personally
interested in pursuing."
About one-third of the 40 physicists who make up the ALPHA
collaboration are Canadian. The rest are from Brazil, Denmark, Israel, Japan,
Sweden, the U.K. and the U.S.
Canadian funding for the project comes from NSERC (National Science and
Engineering Research Council, TRIUMF, AIF (Alberta
The trouble with antimatter
Antimatter is produced in equal quantities with matter when energy is
converted into mass — this happens in particle colliders and is believed to
have happened during the Big Bang at the beginning of the universe. That's why
physicists are puzzled about why there is no longer a significant amount of
antimatter in the universe.
But it's very difficult to study antimatter in order to answer such
questions because antimatter and matter are both annihilated the moment they
encounter each other, producing pure energy.
The problem is our world is made almost entirely of matter, including
the walls of any container that might be used to hold antimatter.
Charged antiparticles can be kept away from the walls of a matter-based
container using electric fields, but neutral antiatoms are much harder to trap,
and are typically annihilated as soon as they are created.
Last November, the ALPHA team reported that it managed to trap
antiatoms by taking advantage of a very tiny, weak magnet inside each atom.
They created the antiatoms by mixing positrons and antiprotons very carefully
inside a "magnetic trap" — a magnetic field generated by a powerful
superconducting magnet. If the newly formed antiatoms were extremely cold and
moving very slowly, the extremely weak magnetic force was enough to keep them
from hitting the walls of the container.
After the experiment, they let the atoms out of the trap
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