Geneva / France – Cern physicists report record measurements

In search of the origin of our existence, physicists at the European Organization for Nuclear Research (CERN) in Geneva have achieved a record measurement. However, the hope of an explanation for why matter and antimatter did not annihilate each other during the Big Bang has been shattered for the time being, as Stefan Ulmer told the German Press Agency. The physicist is the founder of the Baryon Antibaryon Symmetry Experiment (BASE) at Cern, which deals with the properties of antimatter.

“We have not found a difference between protons and antiprotons that could explain the existence of matter in the universe,” said Ulmer of the dpa. When measuring, the physicists compared the masses of protons and antiprotons to eleven decimal places. It cannot be ruled out that differences exist on an even more microscopic and not yet measurable level, said Ulmer. The physicists published their results on Wednesday in the journal “Nature”.

Antimatter describes the antiparticles that exist for every building block in the world, the elementary particles. They have the opposite electrical charge. When particles and antiparticles meet, the pair annihilates each other.

“In essence, it is about the question of the origin of our existence,” said Ulmer. “If we combine the big bang theory and the Standard Model of particle physics, there is really no reason why the universe should come into being.” Because matter and antimatter would have to extinguish each other. Illustrated: if a proton and an antiproton were shaken in a box, nothing would be left. “That must have happened with the Big Bang – but it wasn’t, because we exist,” says Ulmer. «The question” Why do we exist? ” modern physics cannot answer yet. “

One of the theories is that there is an asymmetry between matter and antimatter. If protons were heavier than antiprotons, then – to put it simply – a few protons would be left over in the event of a collision. The experiment at Cern did not reveal any difference with a precision that was previously unattainable. “With a high degree of measurement precision, we ruled out that the difference between matter and antimatter is based on a difference in mass,” said Ulmer.

Individual particles were measured in a 25 centimeter long Penning trap, an electromagnetic container. There the physicists were able to record and compare the oscillations of the proton and antiproton.

Next they want to re-test another theory on the difference between matter and antimatter: whether instead of mass it is perhaps the magnetic moment that differs. The oscillation of the particles around their own axis should be measured with improved precision. “We can now measure with at least ten times more accuracy than before,” says Ulmer.

According to Ulmer, the physicists have for the first time created an experiment that can investigate with the highest precision whether antimatter falls as quickly as matter due to gravity. The preliminary result: Antimatter reacts in the same way as matter. Here, too, one day even more precise measurements may lead to different results, said Ulmer.