Dark energy could be responsible for mysterious experience signals, researchers say

A team of physicists from the University of Cambridge suspect that dark energy may have clouded the results of the XENON1T experience, a series of underground xenon tanks that are used to search for dark matter.

Dark matter and dark energy are two of the most discussed dilemmas in contemporary physics. The dark two are placeholder names for mysterious some things that seem to affect the behavior of the universe and what it contains. Dark matter refers to the seemingly invisible mass that only becomes known through its gravitational effects. Dark energy refers to the still unexplained reason for the accelerating expansion of the universe. Dark matter is believed to make up about 27% of the universe, while dark energy is 68%, according to NASA.

Physicists have a few ideas for explaining dark matter: axions, WIMPs, SIMPs and primordial black holes, to only cite a few. But dark energy is much more enigmatic, and now a group of researchers working on the XENON1T data claim that an unexpected excess of activity could be due to this unknown force, rather than a dark matter candidate. The team’s research was published this week in Physical Review D.

The XENON1T experience, buried under the Apennine mountains in Italy, is set up to be as far away from any noise as possible. It consists of vats of liquid xenon that will ignite when interacting with a passing particle. As previously reported by Gizmodo, in June 2020, the XENON1T team reported that the project was seeing more interactions than it should under the Standard Model of physics, meaning it could detect subatomic particles theorized as axions – or something could be a problem with the experiment.

“These types of excess are often fluids, but every now and then they can also lead to fundamental discoveries,” said Luca Visinelli, researcher at Frascati National Laboratories in Italy and co-author of the study. , at a Cambridge University. Release. “We explored a model in which this signal could be attributable to dark energy, rather than the dark matter that the experiment was originally designed to detect.”

“First we have to know that it was not just a fluke,” added Visinelli. “If XENON1T actually saw anything, you would expect to see a similar excess again in future experiments, but this time with a much stronger signal.”

Although it constitutes a large part of the universe, dark energy has yet to be identified. Many models suggest that there may be a fifth force in addition to the four fundamental forces known in the universe, one which is hidden until you get to some of the larger scale phenomena, like the ever-faster expansion of the universe.

Axions sticking out of the Sun seemed a possible explanation for the excess signal, but there were flaws in the idea, as it would require rethinking what we know about stars. “Even our Sun would not agree with the best theoretical models and experiments as well as it does today,” said a researcher. said Gizmodo last year.

Part of the problem with finding dark energy are “chameleon particles” (also called solar axions or solar chameleons), so called for their theoretical capacity to vary in mass according to the quantity of matter which surrounds them. This would increase the mass of the particles when passing through a dense object like the Earth and would make their force on the surrounding masses smaller, like New Atlas Explainbuilt in 2019. The recent research team built a model that uses chameleon screening sound out how does dark energy behave at scales well beyond that of the dense local universe.

“Our chameleon screening stops the production of dark energy particles in very dense objects, avoiding the problems encountered by solar axions,” said lead author Sunny Vagnozzi, a cosmologist at the Kavli Institute for Cosmology in Cambridge, at a university. . Release. “It also allows us to decouple what is happening in the very dense local Universe from what is happening at larger scales, where the density is extremely low.”

The model allowed the team to understand how XENON1T would behave if dark energy was produced in a magnetically strong region of the Sun. Their calculations indicated that dark energy could be detected with XENON1T.

Since the excess was first discovered, the XENON1T team “in any way tried to destroy it”, as a researcher told the New York Times. The stubbornness of the signal is as confusing as it is exciting.

“The authors offer an exciting and interesting possibility of extending the reach of dark matter detection experiments to the direct detection of dark energy,” Zara Bagdasarian, physicist at UC Berkeley told Gizmodo in an email. who was not affiliated with the recent article. “The case study of XENON1T excess is certainly inconclusive, and we have to wait for more data from more experiments to test the validity of the solar chameleon idea.”

The next generation of XENON1T, called XENONnT, is expected to have its first experimental trials Later this year. Upgrades to the experiment will hopefully get rid of any noise and help physicists figure out exactly what’s wrong with the underground detector.

More: What is dark matter and why no one has found it yet?