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Saturday, November 27, 2010

Trapping antimatter

For the first time, physicists at Swansea University have been able to trap anti-hydrogen for study. This Anti-hydrogen Laser Physics Apparatus (ALPHA) project at CERN will allow researchers to directly compare anti-matter and matter, and perhaps yield insights into why the universe looks the way it does.

ALPHA experiment fully assembled.

© Niels Madsen, ALPHA, CERN

Antimatter is the mirror image of regular matter in terms of charge and other subatomic properties. Whereas normal hydrogen is composed of a proton and an electron, anti-hydrogen is composed of an antiproton and a positron. Antimatter has been predicted for nearly a century, and experimentally produced for nearly a decade. However, until now, there has been no way to affectively study antimatter. This is because antimatter is instantly annihilated upon contact with regular matter. In other words, there hasn’t been any possible container for long-term study of antimatter.

Enter Mike Charlton and his colleagues. They devised a way of cooling and slowing anti-particles (antiprotons and positrons) so that they can form anti-hydrogen. This part wasn’t new. The innovation was in using magnetic coils to trap the anti-hydrogen after it’s created.

These sorts of experiments have a very long lead time. The physicists involved expect to begin running experiments on their anti-hydrogen atoms in about five years. I’ll try to keep you posted.