International collaboration measures velocity of antihydrogen atoms
An international team of scientists has measured the velocity of slow moving or 'cold' antihydrogen atoms for the first time. The ATRAP collaboration, which brings together Harvard University from the US, Germany's Forschungszentrum Jülich and Max Planck institute and the UK's University of York, is working towards capturing large numbers of cold antihydrogen atoms in a trap. The team is working at CERN, the European organisation for nuclear research. The development puts the ATRAP team well on the way to understanding anti-elements. The results will also undoubtedly be used for further fundamental physics research, possibly including the most accurate test yet of charge, parity and time reversal (CPT) symmetry - the fundamental symmetry under transformations that involve the inversions of charge, parity and time simultaneously. Symmetry is regarded as a fundamental property of physical laws. In order to measure the velocity of antihydrogen atoms, the ATRAP team first produced the atoms, which they have been able to do since a breakthrough in 2002. They then applied a moving electric field and counted the fraction of anti-atoms that passed through the field as the oscillation frequency was increased. The cold atoms were therefore ionized as they passed through the electric field. The consortium has measured the field needed to ionize antihydrogen atoms, and found that anti-atoms are formed in highly excited states. The ATRAP team is therefore hypothesising that a third body carries away the energy and momentum liberated by the anti-atom's formation. The experiment has enabled scientists to measure the physics of antihydrogen for the first time, and represents a step towards precision measurements and thus comparisons of matter and anti-matter.
Kraje
Germany, United Kingdom, United States