Scientists believe they have solved one of the oldest problems in the universe

It’s one of the oldest problems in the universe: since matter and antimatter annihilate each other on contact, and both forms of matter existed at the moment of the Big Bang, why is there a universe that consists primarily of matter rather than nothing at all? Where did all the antimatter go?

“The fact that our current universe is dominated by matter remains among the most confounding and long-standing mysteries of modern physics,” said Yano Koi, professor of physics and astronomy in Riverside, UCLA. in the current situation I shared it this week. “A subtle imbalance or asymmetry between matter and antimatter in the early universe is required to achieve the dominance of matter today but cannot be achieved within the known framework of fundamental physics.”

There are theories that may answer this question, but it is very difficult to test them using laboratory experiments. At the moment new paper Published Thursday in the magazine physical review messagesDr. Cui and her co-author, Zhong-Zhi Xianyu, assistant professor of physics at Tsinghua University, China, explain that they may have come up with work on using the afterglow of the Big Bang itself to conduct the experiment.

The theory that Dr. Tsui and Chung-Chi wanted to explore is known as leptogenesis, a process involving the decay of particles that could lead to the asymmetry between matter and antimatter in the early universe. In other words, the asymmetry in certain types of elementary particles in the early moments of the universe could have grown over time and through more particle interactions into the asymmetry between matter and antimatter that made the universe as we know it – and life – possible.

“Leptogen formation is among the most compelling mechanisms that generate matter-antimatter asymmetry,” Dr. Cui said in a statement. “It involves a new fundamental particle, the right-handed neutrino.”

Dr. Coy added that generating the right-hand neutrino requires much more energy than can be generated in particle collisions on Earth.

“Testing leptogen formation is next to impossible, because the mass of the right-handed neutrino is usually in large numbers that exceed the capacity of the largest collider ever made, the Large Hadron Collider,” she said.

The view of Dr. Koi and her co-authors was that scientists might not need to build a more powerful particle collider, because the very conditions they would like to create in such an experiment already existed in some parts of the early universe. The inflationary period, the era of the same exponential expansion of time and space that lasted for milliseconds after the Big Bang, ….

“Cosmic inflation provided a very energetic environment, allowing the production of new heavy particles in addition to their interactions,” said Dr. Coy. “The inflationary universe behaved just like the cosmic collider, except that the energy was up to 10 billion times greater than any man-made collider.”

Moreover, the results of these natural Cosmic Collider experiments may be preserved today in the distribution of galaxies, as well as the cosmic microwave background, the afterglow of the Big Bang from which astrophysicists have drawn much of their current understanding of the evolution of the universe. .

“Specifically, we show that the underlying conditions for asymmetry generation, including the interactions and masses of the right-hand neutrino, which is the key player here, can leave distinct imprints in the statistics of the spatial distribution of galaxies or the cosmic microwave background,” said Dr. Making these measurements, however, remains to be done, she added. “Expected astrophysical observations in the coming years could detect such signals and reveal the cosmic origin of matter.”