A rare particle may have been the reason why there is something instead of nothing.
The theory is that at the beginning of the universe, it was made up of equal parts matter and antimatter. When matter and antimatter meet, they annihilate each other, releasing energy equal to their mass in the form of light. After the big bang, the annihilation of matter and antimatter should have resulted in a big nothing, but something happened that tipped the scales in the direction of matter. One of the old unsolved mysteries of cosmology is what could have happened.
Researchers at the University of California and China’s Tsinghua University have come up with a theory that could be a potential solution to the question: the cosmic particle accelerator. Today’s most powerful particle accelerators, such as the Large Hadron Collider, produce very heavy elementary particles, but the early universe may have been an even more energetic super particle accelerator.
Yanou Cui, professor of astronomy and physics at the University of California, pointed out that the Big Bang was followed by cosmic inflation, which led to an exponential expansion of the Universe.
The cosmic inflation was a very energetic environment, with the production and interaction of large amounts of heavy particles. The inflating Universe acted as a cosmic particle accelerator, but with tens of billions of times the energy of any man-made accelerator – explained Cui, who said that the microscopic structures created during inflation expanded with the Universe and were effectively the nuclei of the fluctuations in the density of matter in the Universe.
According to Cui and Professor Xianyu Tongji of Chinghua University, the cosmic accelerator concept is an approach that can be used to interpret data from, for example, the SPHEREx experiment, which measured the structure of the universe.
The fact that matter dominates the universe today remains one of the oldest and most puzzling mysteries of modern physics. There must be a hidden imbalance between matter and antimatter that causes matter to prevail, but current physics has no explanation. – said Cui.
One possible explanation, the researchers say, is leptogenesis. Leptogenesis is a well-known theory that the creation of leptons (electrons and neutrinos) has upset the matter-antimatter balance. The currently known neutrinos are all left-handed, their antineutrino counterparts are right-handed. The existence of right-handed neutrinos and left-handed antineutrinos is not ruled out, but these are theoretically very massive particles.
Leptogenesis is the most exciting mechanism for the generation of matter-antimatter asymmetry. One of its players is a new elementary particle, the right-handed neutrino. It has long been thought that the theory of leptogenesis is almost uncontrollable because the mass of the right-handed neutrino is several orders of magnitude above the highest energy achievable in the Large Hand Collider. – explained Cui.
Scientists believe that the solution to this problem is to verify the theory of leptogenesis by statistically examining the spatial distribution of cosmic structures.
We have demonstrated that the right-handed neutrinos and their interactions, which are necessary for asymmetry to arise, have left detectable fingerprints on the spatial distribution of galaxies and cosmic microwave background radiation that can be accurately measured. Astrophysical observations expected in the coming years could detect these signals, potentially unravelling the cosmic mystery of matter. – he said.