Research highlight

Upping the anti

Nature Physics

June 6, 2011

The creation, trapping and storage of antihydrogen atoms for up to 1,000 seconds is reported online in Nature Physics this week. This achievement not only represents the longest time period so far that antihydrogen has been captured, but it also brings us closer to answering the question: ‘Do matter and antimatter obey the same laws of physics?’

Antimatter particles are routinely produced in particle accelerators as well as in space, but holding onto them, particularly the neutral ones, is the main difficulty. This is because antimatter and matter will annihilate on contact and conventional containers are made of matter. The ALPHA collaboration at CERN demonstrated last year that they could instead use a magnetic trap to capture antihydrogen particles, and managed to store them for 172 milliseconds. The team now increase that period by more than 5,000-fold, meaning that the antihydrogen atoms have time to reach their ground state, rather than only existing in the highly excited states created by previous experiments, in which they are quickly annihilated. Such long storage times allowed the first measurements of the characteristics of trapped anti-atoms, which provide information about the formation dynamics of antihydrogen atoms and their kinetic energy distribution.

Improved traps will potentially provide plenty of interaction time for future experiments to probe the anti-atoms’ quantum nature with lasers or microwaves, or to cool them down to study the gravitational effects on antimatter.

doi: 10.1038/nphys2025

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