A paper published online yesterday (Sunday, June 5, 2011) by the leading science journal Nature Physics reports that scientists at CERN in Geneva – including physicists from Swansea University – have succeeded in trapping antimatter atoms for over 16 minutes.
The ALPHA (Anti-hydrogen Laser PHysics Apparatus) project’s latest report, entitled “Confinement of Antihydrogen for 1,000 Seconds”, details how the team have created, trapped, and stored some antihydrogen atoms long enough to begin to study them in detail.
This significant development builds on the experiment’s major advance last November, when atoms of antimatter were trapped for the first time.
It is the longest time period so far that antihydrogen has been captured, which means that the antihydrogen atoms have time to reach their ground state, rather than only existing in the highly excited states created by previous experiments.
Professor Mike Charlton, who leads the team of physicists involved in the experiment from Swansea University’s College of Science, said: “Our aim is to study antihydrogen, and make detailed with comparisons with ordinary hydrogen. Whilst hydrogen is the most abundant element in the Universe, it seems that antihydrogen has only ever been formed in our experiments here on Earth.
“Why there was no antimatter left when the Universe became cold enough for atoms to form remains a great mystery – and one we hope to shed some light upon.
“The manner in which we have achieved this latest success bodes well for future experiments aimed at studying the properties of this unique object.”
The Swansea team – comprising Professor Mike Charlton, Dr Niels Madsen, Dr Dirk Peter van der Werf and Dr Stefan Eriksson – are an important part of the international ALPHA collaboration at CERN.
The project also involves physicists from the University of Liverpool, led by Professor Paul Nolan. The work is supported by the Engineering and Physical Sciences Research Council (EPSRC).
Controlled production of antihydrogen atoms in the laboratory has been possible for nearly a decade, when the ATHENA project, also based at CERN, made its first breakthrough.
Swansea University physicists were also major players in ATHENA, the first experiment to produce copious amounts of cold antihydrogen. However, all of these anti-atoms were quickly annihilated when they came into contact with matter. This has now changed with the latest ALPHA breakthrough.
Nonetheless, painstaking preparation of the antiparticles is necessary to trap antihydrogen as the state-of-the-art ALPHA apparatus can only hold atoms with an energy a 100 billion times lower than that of the particles delivered by CERN.
“This latest development is a huge step towards measurements on antihydrogen and we are planning first experiments for later in the year,” said Swansea University physicist Dr Niels Madsen, who is currently on sabbatical at CERN after winning a prestigious Royal Society Leverhulme Trust Senior Research Fellowship.
“We have increased the efficiency with which we trap the antihydrogen atoms and held onto some of them for long periods, already increasing our capability several thousand times over what we reported last November.”
To view the “Confinement of Antihydrogen for 1,000 Seconds” paper, published online by Nature Physics, visit http://www.nature.com/nphys/index.html.
And for further information about Swansea University’s Department of Physics visit http://www.swansea.ac.uk/physics/.
