The subatomic particles may already solve two important puzzles of particle physics
Science News said:Chalk up a potential third win for hypothetical particles called axions.
If the subatomic particles exist, they could solve two pressing puzzles of particle physics: the source of the dark matter that fills galaxies with invisible mass, and the reason why interactions between quarks — the particles that make up protons and neutrons — adhere to a certain symmetry of nature, called CP symmetry, that other types of particle interactions eschew.
Now, two researchers say that axions could solve a third thorny problem: why the universe is made mostly of matter, while antimatter is rare. In the early universe, the axion could have behaved in a manner that produces an excess of matter, particle physicists Raymond Co and Keisuke Harigaya suggest in the March 20 Physical Review Letters.
“They have an idea which has all the right ingredients to do some interesting things,” says physicist Michael Dine of the University of California, Santa Cruz. But it remains to be seen whether the idea can fully reproduce the properties of the cosmos, he says. “This is one of those cases where the devil is in the details.”
Scientists think that 13.8 billion years ago, the Big Bang birthed equal parts matter and antimatter. Since matter and antimatter particles annihilate when they meet, that would have left a universe filled with pure energy. So, as the universe evolved, some process must have favored matter over antimatter, but scientists still don’t know for sure how it happened. Some researchers think, for example, that neutrinos played a role (SN: 11/25/19).
Now Co, of the University of Michigan in Ann Arbor, and Harigaya, of the Institute for Advanced Study in Princeton, N.J., propose a new idea for how matter gained the upper hand. It’s based on the evolution of the axion field, a hypothetical ethereal blanket that permeates space, similar to how an electric field extends around an electric charge.
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