Why is there no antimatter in the universe? The Cosmological Collider may provide the answer

(ORDO NEWS) — Scientists suggest that the reason for the dominance of matter over antimatter lies in the superheavy right-handed neutrinos. If the inflationary model is correct, traces of the existence of these microparticles should have been reflected in the large-scale structure of the Universe.

Researchers from the University of California at Riverside (USA) and Tsinghua University (China) have proposed a way to solve one of the main mysteries of modern physics – the baryon asymmetry of the Universe.

According to their calculations, the observed dominance of ordinary matter can be explained by the decay of heavy right-handed neutrinos in the first moments of the life of the Universe.

If the inflationary theory is correct, then traces of these neutrinos can be found in the inhomogeneities of the distribution of galaxies and cosmic microwave background radiation in outer space, the scientists write in Physical Review Letters.

Antimatter is atoms mirrored in electric charge. For example, if a hydrogen atom has a positively charged nucleus and a negatively charged electron, then an antihydrogen atom consists of a negatively charged nucleus and a positively charged electron.

Existing physical theories like the Standard Model and general relativity say that there should be as much antimatter in the universe as there is matter. Such symmetries are generally natural for nature, while symmetry violations must be justified separately.

However, in reality, scientists observe the absolute dominance of ordinary matter. Galaxies, stars, planets and living beings are created from it, while antimatter has never been recorded in significant quantities. Generally speaking, this is good news for people.

When antimatter meets matter, it annihilates that is, it explodes with the maximum possible power, converting all mass into energy.

If the Universe produced an equal amount of matter and antimatter, then they would mutually destroy each other, filling the world with pure radiation instead of galaxies, stars and planets with living beings.

But for scientists, the observed asymmetry between matter and antimatter is one of the biggest problems that needs to be addressed.

Why is there no antimatter in the universe The Cosmological Collider may provide the answer 2
Signs of the presence of right-handed neutrinos against the background of ordinary left-handed signals

Physicists propose to look for the answer to the problem of the baryon asymmetry of the Universe in the decay of right-handed (or sterile ) neutrinos. These are hypothetical neutrinos whose spin projection coincides with the direction of their motion.

Hypothetical – because they do not occur in nature and it is impossible to create them on your own (unlike antimatter). Too much energy will have to be spent on this, even the Large Hadron Collider will not cope.

But in the first moments of the existence of the Universe (about 10 to -36 seconds), the energy density was 10 trillion times higher than in the LHC, and right-handed neutrinos should have appeared in excess. Their subsequent decay could cause the baryon asymmetry of the Universe.

However, there is no need to test this theory experimentally if one can go directly to the history of the universe using the inflationary model. This model is designed to explain the apparent homogeneity of the universe, which the Big Bang theory cannot explain.

According to the inflationary model, the Universe in the first moments of its life expanded at an enormous rate (in a millionth of a second, the volume increased by a factor of 10 to the 78th power), and the slightest quantum fluctuations were imprinted in the observed large-scale structure of the cosmos.

This means that in this structure one can also find imprints of the existence of right-handed neutrinos. This approach is called the cosmological collider, where the role of the collider (particle accelerator) is played by the period of inflationary expansion of the Universe.

This is the essence of the new work of physicists from the US and China: they show how the cosmos can store traces of the processes that took place during the period of inflationary expansion.

According to Yanou Cui of the University of California, these superheavy particles should have left distinct imprints of their existence in the three-dimensional structure of the universe, which can be found with telescopes in the coming years. Then one of the main mysteries of physics will finally be solved.


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