Spectrum of anti-hydrogen observed
By
Joe Mount
13 April 2017
The ALPHA-2 (Anti-Hydrogen Laser Physics Apparatus) experiment has made the first observations comparing the light emitted from hydrogen atoms made of antimatter to the light emitted from hydrogen atoms made of ordinary matter. The results indicate that the underlying characteristics of matter and antimatter differ by at most 200 parts per trillion, a significant milestone for research into antimatter and particle physics in general.
ALPHA is one of many international scientific collaborations operating out of the CERN (European Organization for Nuclear Research) laboratories near Geneva, Switzerland. It generates and traps atoms of anti-hydrogen, the antimatter counterpart of the simplest atom, hydrogen, to allow for precision comparisons between the two in order to more fully understand the underlying physics governing antimatter.
The exact nature of antimatter is one of the outstanding questions in modern physics. Antimatter was first hypothesized by Paul Dirac in 1928 and worked through more carefully by Dirac and Robert Oppenheimer in 1931. They predicted that certain physical processes would produce particles identical to the well-known electron or proton, except that they would have an opposite electric charge. While the idea was met with some scepticism in the physics community, the existence of the “anti-electron” (more commonly known as a positron) was experimentally verified in 1931 by Paul Anderson. Since then, antimatter equivalents have since been observed for all known fundamental particles.
What has puzzled scientists for nearly a century, however, is the imbalance between the amounts of normal matter and antimatter in the…