Scientists may have found first hint of dark matter

Scientists believe they may be one step closer to detecting dark matter for the first time, but the findings have not been verified by independent researchers.

Scientists from the University of Bristol were part of a two-year study to try and measure the invisible substance thought to make up over 85% of the universe.

Using a sensitive detector in an an underground laboratory in the US, the researchers saw an atom and mystery particle colliding.

Lead researcher physicist Dr Sam Eriksen said it could be "the first step in understanding dark matter as a particle", but further research could also reveal that the particle is not related to dark matter.

"Following a huge amount of scientific effort, this is incredibly exciting," the University of Bristol senior research associate added.

Although scientists have long been certain of the existence of dark matter, because it is invisible as it reflects no light.

While it is thought to make up the majority of mass in the universe, it has never been directly detected.

For two years, 250 scientists and engineers from 39 institutions spanning six countries, including two universities from the UK, have rigorously scrutinised data from one of the world's most sensitive dark matter detectors called LUX-ZEPLIN (LZ).

It is managed by the US Department of Energy's Sanford Underground Research Facility in South Dakota - the deepest laboratory in the US at nearly a mile beneath the ground.

To search for dark matter, LZ uses extremely sensitive light detectors to capture particle interactions.

The study found one particle interaction which could potentially have been caused by a Weakly Interacting Massive Particle, (WIMP), which scientists believe make up dark matter.

But there is currently low statistical evidence in it being a true breakthrough.

The findings were revealed at a conference in Japan on Tuesday, but the research has yet to undergo peer-review by other scientists.

The findings have been rated 2.6 sigma, which is the system that marks the statistical significance of discoveries. The normal threshold is five.

"With only one event, we don't want to get ahead of ourselves," said Professor Rick Gaitskell from Brown University.

"We are not claiming to have seen dark matter. But we have seen something interesting that we want to share with the scientific community for their input."

Professor Henning Flaecher, an experimental particle physicist at the University of Bristol, said a "huge amount" of work had been carried out over "countless hours" to investigate any previously known reasons researchers might have observed the unusual reaction.

"To date none provide a convincing explanation," he said.

"It's an incredibly exciting time, the kind of event every astro-particle physicist dreams of, and we can't wait to analyse more data to see if additional candidate events appear."

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