Dark matter could have been created much earlier than previously thought, UT Department of Physics researchers revealed in a new model published in Physical Review Letters on Nov. 18.
The model, named dark matter production during Warm Inflation via Freeze-In, or WIFI, suggests dark matter began forming before the Big Bang. The uniqueness of the model comes from the fact that dark matter was produced during inflation before the Big Bang, said Katherine Freese, who led the research team. Normally, the accelerated expansion of the universe means anything produced during expansion is diluted to almost nothing.
“(Freeze-In) is the idea that you produce dark matter in the following way,” Freese, a physics professor as well as director of the Weinberg Institute and Texas Center for Cosmology and Astroparticle Physics, said. “You start with no dark matter around, but then as time goes on, other particles start creating the dark matter. So slowly, slowly, dark matter comes into existence.”
Fourth-year Ph.D. candidate Gabriele Montefalcone and postdoctoral researcher Barmak Shams Es Haghi first came up with the idea for the model during a seminar Montefalcone gave about warm inflation, a period before the Big Bang where hot thermal particles were produced during a period of accelerated expansion of the universe. The radiation field present in warm inflation meant that Freeze-In could occur.
Shams Es Haghi told Montefalcone the high energy radiation that exists in warm inflation meant it was possible particles could be produced.
“At the beginning, it was nothing,” Shams Es Haghi said. “We were just curious. Then it turned into weekly meetings. We talked to Professor Freese about that. She was excited. She encouraged us, and we ended up with a very interesting paper at the end.”
Freese helped direct the researchers towards a model that could be used for different applications.
“We wanted to emphasize that this is a very general mechanism,” Montefalcone said. “It’s not going to only work with this specific thing.”
Montefalcone said he developed the numerical codes used for the calculations in the model. Upcoming experiments will test warm inflation, which, if confirmed to be a correct model, could strengthen the case for dark matter production during this time, according to the department website.
“Dark matter is a 90-year-old problem,” Freese said. “We know it’s there, and we can’t figure out what it’s made of, so that’s just extremely frustrating. There are experimental searches looking for it, but it’s still a wide-open field. So having a novel way of making it is important in this grander context of, ‘What is dark matter? Where was it produced?’”
Editor’s note: A previous version of this story gave an incomplete version of a source’s name. This has been corrected. The Texan regrets this error.
