Physicists carried out the first accurate measurements of how light interacts with particles of antimatter, and did not find significant differences in its behavior compared to ordinary matter, which once again made scientists wonder why the universe exists. Their findings were published in the journal Nature.
“These are the first real spectroscopic measurements of the properties of antimatter obtained with lasers. The ultra-high precision of our latest measurements has been a major achievement for our team. We've been trying to reach this target for 30 years, and we have finally managed to realize that dream,”said Jeffrey Hangst, official representative of the ALPHA collaboration.
According to scientists today, in the first moments after the Big Bang, an equal amount of matter and antimatter appeared. At the same time, the Standard Model of Physics says that the properties of antimatter particles mirror the characteristics of their twins, with the exception of the charge. In other words, the chemical and physical properties of the atoms of antimatter and matter must be identical.
Since matter and antimatter annihilate upon collision, during the birth of the Universe, their particles had to destroy each other, depriving the universe of all reserves of both matter and antimatter. Therefore, the question arises - where did the antimatter "disappear" and why the Universe exists.
It is believed that one of the reasons for the "asymmetry of matter" may lie in the existence of small, but rather significant differences in the structure and properties of antimatter particles. In recent years, physicists have found several hints that such differences, for example, in the masses of protons and antiprotons, still exist, but their exact change is hampered by the low accuracy of instruments and the microscopic scale of this asymmetry.
Angst and his colleagues have been trying to find hints of differences in the properties of matter and antimatter for many years using the ALPHA-2 device, a special trap for positrons and antiprotons, forcing them to combine and form single atoms of antimatter. Due to absolute isolation, atoms of antimatter can exist in this trap for several days without decaying or annihilating.
The ALPHA team has long been trying to measure the spectrum of antihydrogen atoms, comparison of which with similar data for hydrogen will show whether light interacts in the same way with two forms of matter, and whether there are even the smallest differences in the mass of their particles.
The first results of this kind were obtained six years and two years ago, but these measurements were not accurate due to the fact that they were not carried out directly, but indirectly, observing the consequences of the collision of particles of antimatter and matter. Scientists were forced to act this way due to the fact that there were too few antihydrogen atoms. This prevented the search for possible traces of the "new physics" and the solution of the mystery of the disappearance of antimatter.
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Angst and his colleagues were able to solve this problem by modifying the structure of the trap in such a way that it allowed them to irradiate antihydrogen with seven types of laser beams at once. By combining pictures obtained during such "shelling", scientists were able to increase the accuracy of measurements by 100 times and achieve a level of error not exceeding two parts per trillion. This is only three orders of magnitude less than the accuracy achieved when "firing" hydrogen.
As in the last two times, the spectra of matter and antimatter completely coincided, which suggests that they interact with light in the same way and, presumably, have identical mass. Coupled with other recent measurements of other properties of antiprotons, this discovery makes scientists increasingly wonder where the difference between matter and antimatter is "hiding".
The first answers to these questions, as Angst and his colleagues hope, will be received very soon, when ALPHA-2 is modernized and expanded, which will increase the accuracy of spectrum measurements by several orders of magnitude and come closer to solving the mystery of the existence of the Universe.