A nuclear reactor experiment rules out one dark matter hope

Dark matter makes up more than a quarter of the universe, but it remains shrouded in mystery

Dark matter makes up more than a quarter of the universe, but it remains shrouded in mystery.

An anomaly discovered in a nuclear reactor storm was so baffling that physicists hoped it would shed light on dark matter, one of the universe’s greatest mysteries.

However, the new research has categorically ruled out that this strange measurement indicates the existence of a “sterile neutrino,” a hypothetical particle that has eluded scientists for a long time.

Neutrinos are sometimes called “ghost particles” because they hardly interact with other matter — an estimated 100 trillion of them pass through our bodies every second.

Since neutrinos were first theorized in 1930, scientists have been trying to determine the properties of these shape-shifters, which are one of the most common particles in the universe.

It appears “when the nature of the atomic nucleus changes,” physicist David Lhuillier of the French Atomic Energy Commission told AFP.

This can happen, he said, when they come together in the furious fusion in the cores of stars like our sun, or break apart in nuclear reactors.

There are three confirmed flavors of neutrino: electron, muon, and tau.

But physicists believe there could be a fourth neutrino, called “sterile” because it doesn’t interact with ordinary matter at all.

Theoretically, it will be only the reaction of gravity and not the fundamental force of the weak interaction, which still dominates other neutrinos.

The sterilized neutrino has a ready place for itself in theoretical physics, he added, “but there has been no clear evidence yet of its existence.”

dark matter filter

So Lhuillier and the rest of the members of STEREO, which brings together French and German scientists, set out to find him.

Measurements of previous nuclear reactors have detected fewer neutrinos than the amount predicted by theoretical models, a phenomenon dubbed the “neutrino anomaly in the reactor”.

He suggested that the missing neutrinos had turned out to be the sterile kind, providing a rare opportunity to prove their existence.

To find out the answer, the STEREO collaboration installed a dedicated detector a few feet away from a nuclear reactor used for research at the Laue-Langevin Institute in Grenoble, France.

After four years of monitoring more than 100,000 neutrinos and two years of data analysis, the verdict was published in the journal. nature Wednesday.

The anomalies “cannot be explained by sterilized neutrinos,” Lhuillier said.

He added that this “does not mean that there is nothing in the universe.”

The experiment found that previous predictions of the amount of neutrinos produced were incorrect.

But it wasn’t a complete loss, as it provided a much clearer picture of the neutrinos emitted by nuclear reactors.

This may help not only in future research, but also in monitoring nuclear reactors.

Meanwhile, the search for sterile neutrinos continues. Particle accelerators, which crush atoms, could offer new leads.

Despite the setback, interest could remain high because sterile neutrinos have been deemed a suspect in dark matter, which makes up more than a quarter of the universe but is still shrouded in mystery.

Like dark matter, sterile neutrinos don’t interact with ordinary matter, making them extremely difficult to observe.

“It would be a candidate for why we see dark matter effects — and why we can’t see dark matter,” Lhuillier said.

more information:
David Lhuillier, Stereo Neutrino Spectrum of Fission 235U rejects the sterile neutrino hypothesis, nature (2023). DOI: 10.1038/s41586-022-05568-2. www.nature.com/articles/s41586-022-05568-2

© 2023 AFP

the quote: Nuclear Reactor Experiment Rules Out One Hope for Dark Matter (2023, January 14) Retrieved January 15, 2023 from https://phys.org/news/2023-01-nuclear-reactor-dark.html

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