Tópico: Anti-hidrogênio capturado no CERN

[SnowRaptor]

Antihydrogen trapped at CERN


Physicists at CERN in Geneva are the first to capture and store atoms of antimatter for long enough to study its properties in detail. Working at the lab's ALPHA experiment, the team managed to trap 38 anti-hydrogen atoms for about 170 ms. The next step for the researchers is to measure the energy spectrum of the atoms, which could provide important clues as to why there is much more matter than antimatter in the universe.

Anithydrogen is the antimatter version of the hydrogen atom and comprises a positron – or antielectron – and an antiproton. According to the Standard Model of Particle Physics, the energy levels of anti-hydrogen should be identical to those of hydrogen. Any deviations from this could help physicists identify new physics – and explain why there is much more matter than antimatter in the universe.

Although creating positrons and antiprotons is relatively easy, making antihydrogen is much harder. This form of antimatter was not isolated until 1995 – also in experiments at CERN. Making it stick around for long enough to study in detail is even more difficult. But in being able to trap anti-hydrogen atoms for 170 ms, the members of ALPHA, who come from 14 institutions in seven different nations, can now look forward to studying its atomic energy levels.

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"For reasons that no one yet understands, nature ruled out antimatter. It is thus very rewarding, and a bit overwhelming, to look at the ALPHA device and know that it contains stable, neutral atoms of antimatter," said ALPHA spokesperson Jeffrey Hangst of Aarhus University in Denmark. "This inspires us to work that much harder to see if antimatter holds some secret."

The work is described in Nature doi:10.1038/nature09610.

About the author
Hamish Johnston is editor of physicsworld.com