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

Scientists think they have solved one of the oldest problems in the universe
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It’s one of the oldest problems in the universe: Ever since issue and antimatter they destroy each other on contact and both forms of matter existed at the time of creation big bang, why is there a universe made primarily of matter rather than nothing? Where did all the antimatter go?

“The fact that our present universe is dominated by matter remains among the most puzzling, long-standing mysteries of modern physics,” said Yanou Cui, professor of physics and astronomy at the University of California, Riverside. in the statement shared this week. “A subtle imbalance, or asymmetry, between matter and antimatter in the early universe is required to achieve the predominance of matter today, but cannot be realized within the known framework of fundamental physics.”

There are theories that can answer this question, but they are quite difficult to test using them laboratory experiences. Now, in new paper published on Thursday in the magazine Physical review lettersDr Cui and his co-author Zhong-Zhi Xianyu, associate professor of physics at China’s Tsinghua University, explain that they may have found something to do by using the afterglow of the big bang itself to carry out the experiment.

The theory that Drs Cui and Zhong-Zh want to explore is known as leptogenesis, a process involving the breakdown of particles that may have caused an asymmetry between matter and antimatter in the early universe. In the earliest moments of the cosmos, an asymmetry in certain types of elementary particles, in other words, could, over time and through subsequent interactions of particles, become an asymmetry between the matter and antimatter that makes the universe and life as we know it. possible.

“Leptogenesis is one of the most compelling mechanisms for creating matter-antimatter asymmetry,” said Dr Cui. “It includes a new fundamental particle, the right-handed neutrino.”

But, Dr Cui added, creating a right-handed neutrino would require much more energy than what can be produced in particle colliders on Earth.

“Leptogenesis is impossible to test because the mass of right-handed neutrinos is usually of an order of magnitude beyond the reach of the Large Hadron Collider, the highest energy collider ever built,” he said.

According to Dr Cui and his co-authors, scientists may not need to build a more powerful particle collider because the conditions they want to create in such an experiment already existed in parts of the early universe. The inflationary era, the epoch of exponential expansion of time and space itself, lasted only fractions of a second after the big bang, ….

“Cosmic inflation provided a high-energy environment, enabling the production and interaction of heavy new particles,” Dr Cui said. “The inflationary universe behaved like a cosmological collider, but the energy was 10 billion times greater than any human-made collider.”

Moreover, the results of those natural cosmological collider experiments can be preserved in their distribution even today galaxiesas well as the cosmic microwave background, the afterglow of the big bang from which astrophysicists derive much of their current understanding of the evolution of the cosmos.

“In particular, we show that important conditions for the asymmetry, including the interactions and masses of right-handed neutrinos, a key player here, can leave different fingerprints on the statistics of the spatial distribution of galaxies or the cosmic microwave background. It can be precisely measured,” said Dr. Cui, although making these measurements remains to be seen. “Expected astrophysical observations in the coming years could potentially provide such signals and reveal the cosmic origin of matter.”

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