Please read this paper for additional information on this discovery.
And, a paper within the journal Nature summarizes the work of these physicists. It is called 'Trapped antihydrogen' (November 17, 2010; doi:10.1038/nature09610;).
It is authored by an international team of scientists from Denmark, Canada, the United States, Brazil, Sweden, the United Kingdom, Israel, Japan, and Switzerland.
Why is this development so important?
This development within particle physics -- producing and trapping atoms of anti-hydrogen -- could provide detailed measurements of anti-hydrogen. Consequently, it could lead to a comparison of matter and its counterpart: anti-matter.
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