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Where is dark matter? Another experiment can not find a signal



Sodium iodide crystals from COSINE-100
Photo: COSINE-100

An experiment with dark matter in South Korea could soon confirm or deny outstanding evidence of dark matter.

The observations of the universe show that this is the case consists mainly of things that scientists do not understand. Normal matter seems to be less than 5 percent of the universe, dark energy is 68 percent, and the rest is dark matter, mysterious things discovered only by gravity. Recently, an experiment called DAMA / LIBRA in Italy claimed to have found evidence of this dark matter. A new experiment, COSINE-100, has just released its own results – but the signal from DAMA / LIBRA has not been detected.

"What we can say is spin-independent dark matter," which refers to a simpler theoretical model of dark matter, "does not cause the DAMA signal," said Reina Maruyama, Associate Professor of Physics in Yale, to Gizmodo ,

Physicists at DAMA / LIBRA in Italy have reported an annual signal in the sodium iodide crystal detectors of the experiment that would emit A juvenile flash of light should pass a hypothetical particle of dark matter and give an impetus. The researchers interpret this as a varying amount of dark matter that changes due to the orientation of the Earth relative to the rest of the galaxy. COSINE-100 is another experiment with 106 kilograms of sodium iodide crystals located in the Yangyang Underground Laboratory in South Korea.

Scientists used COSINE-100 to capture data from October 20, 2016 and December 19, 2016, and found no evidence of dark matter that DAMA / LIBRA reportedly discovered. Although other experiments have not picked up the signal, COSINE-100 is the first to be made from the same sodium iodide. Therefore, the failure to confirm the DAMA / LIBRA results is an even clearer indication that the Italian experiment may not be aware of dark matter.

DAMA / LIBRA spokeswoman Rita Bernabei from the University of Rome, Tor Vergata, told Gizmodo that the results of COSINE-100 will not change anything. She did not believe that COSINE-100 was as sensitive to dark matter interactions as the scientists claimed, and that the signal could still occur if a "more correct, realistic, and reliable" model of the potential background noise source were needed. Dan Hooper, a physicist at the University of Chicago, told Science News that the COSINE 100 results are "another nail in the coffin".

This is just the first leg of the work of the South Korean experiment, Maruyama said to Gizmodo. The team was only looking for signals above the background noise and still has to look for annual modulations like the annual signal sent by DAMA / LIBRA. Other sodium iodide detectors will also try to validate the earlier claims, as we have reported.

However, if a second experiment of the same material fails to validate the first claim, it is a sign that the alien signal is present. Detected DAMA / LIBRA may not be dark matter.

[Nature]


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