Scientists Observe Light from Antimatter; Unique Optical Spectrum Explained
Scientists have just managed to make the first ever measurement of the optical spectrum of an antimatter atom. This achievement by the ALPHA collaboration opens a completely new era in high-precision antimatter research.
According to a press release from CERN, this marks the result of over 20 years of work by its antimatter community.
Jeffrey Hangst, spokesperson of the ALPHA collaboration, said observing the transition in antihydrogen and comparing it to hydrogen via laser is an integral component in checking whether or not they follow the same laws of physics.
It can be remembered that atoms consist of electrons orbiting a nucleus, and when electrons move from one orbit to the next, they absorb and emit light at specific wavelengths.
This forms the atom's spectrum, meaning each element has a unique spectrum they can be identified with.
This means spectroscopy has become a commonly used tool in many areas of physics, astronomy and chemistry as it helps characterize atoms and molecules and their internal goings-on. For instance, in astrophysics, analyzing the light of remote stars can help scientists determine their composition.
According to Science News, the hydrogen is the most common and well-understood atom in the universe, given it only has a single proton and electron. Its spectrum has been measured with quite the high precision.
However, antihydrogen atoms are poorly understood because the universe appears to consist entirely of matter. This means the constituents of antihydrogen atoms - antiprotons and positrons - had to be produced and assemble.
However, according to Gizmodo, while the effort may have been cumbersome, understanding the differences between hydrogen and antihydrogen can break the basic principles of physics and help understand the matter-antimatter balance in the universe.
The ALPHA observation is the result of the first observation of a spectral line in an antihydrogen atom. This allows the light spectrum of the matter and antimatter to be compared for the first time.
Within the experimental limits, the results show no difference compared to the equivalent spectral line in hydrogen. This means its consistent with the Standard Model of particle physics, the model that describes the particles and the forces at work between them.
This proves the initial prediction that hydrogen and antihydrogen should have identical spectroscopic characteristics.
The ALPHA collaboration wants to improve the precision of its measurement in the future, this time checking if matter behaves differently from antimatter.
ALPHA is a unique experiment at CERN's Antiproton Decelerator facility, as it is able to produce antihydrogen atoms and hold them in a specially designed magnetic strip.
Antihydrogen is created by mixing plasmas of about 90,000 antiprotons from the Decelerator with positrons, creating about 25,000 antihydrogen atoms per attempt.
They can be trapped if they move slow enough when they are created. Using a new technique that stacks anti-atoms, it is possible to trap 14 anti-atoms per trial.
Illuminating the trapped atoms can observe the interaction between the beam and the internal states of hydrogen.