COSINE-100 experiment investigates darkish matter thriller — Sc…
Yale scientists are a part of a brand new worldwide experiment that challenges earlier claims in regards to the detection of non-luminous darkish matter.
Astrophysical proof means that the universe accommodates a considerable amount of non-luminous darkish matter, but no particular sign of it has been noticed regardless of concerted efforts by many experimental teams. One exception to that is the long-debated declare by the DArk MAtter (DAMA) collaboration, which has reported optimistic observations of darkish matter in its sodium-iodide detector array.
The brand new COSINE-100 experiment, based mostly at an underground, dark-matter detector on the Yangyang Underground Laboratory in South Korea, has begun to discover DAMA’s declare. It’s the first experiment delicate sufficient to check DAMA and use the identical goal materials of sodium iodide.
COSINE-100 has been recording information since 2016 and now has preliminary outcomes that problem the DAMA findings. These findings are revealed on-line this week within the journal Nature.
“For the first time in 20 years, we have a chance to resolve the DAMA conundrum,” mentioned Yale physics professor Reina Maruyama, who’s co-spokesperson for COSINE-100 and co-author of the brand new examine.
The primary section of COSINE-100’s work searches for darkish matter by on the lookout for an extra of sign over the anticipated background within the detector, with the proper power and traits. On this preliminary examine, the researchers discovered no extra of sign in its information, placing DAMA’s annual modulation sign at odds with with outcomes from different experiments. COSINE-100 scientists famous that it’ll take a number of years of information to totally affirm or refute DAMA’s outcomes.
The COSINE-100 experiment makes use of eight low-background, thallium-doped sodium iodide crystals organized in a 4-by-2 array, giving a complete goal mass of 106 kg. Every crystal is coupled by two picture sensors to measure the quantity of power deposited within the crystal.
The sodium iodide crystal assemblies are immersed in 2,200 L of light-emitting liquid, which permits for the identification and subsequent discount of radioactive backgrounds noticed by the crystals. The detector is contained inside a nested association of copper, lead, and plastic shielding elements to cut back the background contribution from exterior radiation, in addition to cosmic ray muons.
The COSINE-100 collaboration contains 50 scientists from the U.S., South Korea, the UK, Brazil, and Indonesia. The Yangyang Underground Laboratory, the place the experiment relies, is operated by the Middle for Underground Physics of the Institute for Primary Science (IBS) in South Korea.
“The initial results carve out a fair portion of the possible dark matter search region drawn by the DAMA signal. 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,” mentioned Hyun Su Lee, the opposite co-spokesperson for COSINE-100, and an affiliate director of the Middle for Underground Physics at IBS.
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