A new international experiment, named COSINE-100, is currently underway at South Korea's Yangyang Underground Laboratory to investigate a previous claim about the detection of non-luminous dark matter.
Evidence collected through observations of galaxies and radiation suggests that the universe comprises of huge amounts of non-luminous dark matter. Scientists have also proposed some particles as potential candidates for dark matter, although no direct observation of any such particle or the mysterious dark matter has been made so far.
However, there is one exception - the claim by the DArk MAtter (DAMA) collaboration, which reported positive observations of nuclear interaction event (thought to be caused by dark matter) in sodium-iodide detector array.
Now a new collaboration, involving scientists from the U.S., UK, South Korea, Brazil, and Indonesia, has commenced the COSINE-100 experiment to explore DAMA's claim. The experiment is running at an underground detector at Yangyang Lab in South Korea. The experiment, which also uses sodium iodide as the target material, started recording data in September 2016, and the preliminary results from the experiment challenge the DAMA's claim.
"For the first time in 20 years, we have a chance to resolve the DAMA conundrum," said Reina Maruyama, Yale physics Professor, who is also co-spokesperson for the COSINE-100 experiment.
The first phase of COSINE-100 experiment deployed eight thallium-doped sodium iodide crystals [NaI(Tl)] arranged in a 4 x 2 array. Each crystal is coupled by two photo sensors to measure energy in the crystal. The total mass of the target material in the experiment is 106 kilograms.
COSINE-100 will look for an excess of signal over the expected background in the detector. The team reported "no excess of signal-like events above the expected background in the first 59.5 days of data from COSINE-100."
"The initial results carve out a fair portion of the possible dark matter search region drawn by the DAMA signal," said Hyun Su Lee, a co-spokesperson for COSINE-100 experiment and associate director of the Centre for Underground Physics at the Institute for Basic Science in South Korea.
"In other words, there is little room left for this claim to be from the dark matter interaction unless the dark matter model is significantly modified."
The experiment will run for two more years to collect additional data to fully confirm or negate DAMA's results.
The findings of the study are published in the journal Nature.
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