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Antimatter behaves 'normally' helping to understand where it all went.

Nature reports results from ALPHA, CERN. Jeff Hangst, IFA is coauthor.

The charge of antihydrogen — the antimatter counterpart of hydrogen — is neutral, confirms a new study published in this week’s Nature. Antimatter is thought to have appeared in a quantity equal to that of matter after the Big Bang, but, intriguingly, it appears to be absent from the observable Universe. Recently it has become possible to study artificially created atoms of antihydrogen in an effort to search for possible differences in behaviour between matter and antimatter.

According to the Standard Model of particle physics, the charge of antihydrogen should be neutral, but this has been difficult to test because producing antimatter and measuring its properties is experimentally challenging. As part of the ALPHA Collaboration at CERN, Jeffrey Hangst and colleagues study trapped atoms of antihydrogen and provide strong evidence for their charge neutrality: they improve measurement precision of the charge of antihydrogen by a factor of 20 compared to previous measurements. Since the charge of the antiproton (the antimatter counterpart of the proton) is known to similar precision, this result also helps to refine the bound on the charge of the positron (the antimatter counterpart of the electron).

 These measurements constitute a test of the fundamental requirements of the Standard Model and may help address the long-standing question of why there appears to be so much more matter than antimatter in the observable Universe. 

 The article is titled "An improved limit on the charge of antihydrogen from stochastic acceleration". I can be found here: ): http://dx.doi.org/10.1038/nature16491

Further information contact ?Jeffrey Hangst (Aarhus University, Aarhus, Denmark) 

Tel: +41 75 411 4589; E-mail: jeffrey.hangst@cern.ch