The quest to find the most mysterious matter in the universe

From deep underground, in abandoned gold and nickel mines, containers of liquid xenon and germanium crystals are used to detect dark matter particles.

10 tons of liquid xenon are being pumped into tanks located nearly 1.2 km underground, near the center of an old gold mine in South Dakota, USA. With this huge chemical barrel, scientists hope to discover the mysterious material that accounts for more than 85% of the total mass of the universe: Dark matter.

LUX-ZEPLINE (LZ) is one of three major experiments funded to detect information about dark matter, the type of matter that has been teasing science for over thirty years.

Previous tests such as LUX, the precursor to LZ, were carried out in a relatively short time, so this next project hopes to address the challenge by using systems of scale and sensitivity yet. have ever seen it before.

The LUX-ZEPLINE detector will be filled with 10 tons of liquid xenon, dark matter particles passing through will flash.(Photo: SLAC).

"Specter of the Universe"

The first concept of dark matter originated in 1930, when astronomer Fritz Zwicky tracked the velocity of more than 1,000 galaxies gathered together. He observed that visible gravity is only strong enough to keep the cluster from flying. From there, he said that there was the presence of 'dark matter'.

40 years later, astronomers Vera Rubin and Kent Ford found much evidence of dark matter by studying the motion of stars in the spiral galaxy.

Most recently, two colliding galaxies called the Bullet Cluster cause gravitational lenses - the effect of light being bent by enormous gravity that cannot be explained using only visible particles.

The scientists conclude that these observations strongly indicate the existence of dark matter , but exactly what this material was created for is still a mystery.

Bullet galaxy clusters create gravitational lens effects.The image was synthesized from the Hubble, Chandra and Magellan telescopes, with the pink portion showing X-rays emitted from the hot gas, while blue is thought to react with dark matter.(Photo: NASA, CXC, CfA).

To find dark matter, physicist Priscilla Cushman - spokesman for another dark matter detection experiment , SuperCDMS SNOLAB , is studying dark matter through experiments that affect ordinary matter particles.

Scientists try to create dark matter by smashing two high-energy protons into each other in a large particle accelerator, mimicking what could have happened in the Big Bang. all this particles form.

Experiments such as LZ and SuperCDMS are expected to detect dark matter when interacting with normal matter through a weak force through extremely sensitive signals from detectors.

However, the physical indicators of dark matter have only been theorized, Cushman said that everything is still like digging a needle in the seabed.

The most common type of matter in the universe

The most widely known dark matter particle is the WIMP. WIMP stands for Weakly interacting massive particles - the particles have great mass but the interaction force is very weak.

WIMP became popular after theoretical physicists thought that if weakly interacting particles weighed more than 100 times a proton generated from the Big Bang, their density would now account for the entire number of objects. Estimated dark matter exists in the universe. LZ and SuperCDMS are both designed to detect WIMP.

The LUX-ZEPLINE and SuperCDMS SNOLAB experiments are both located deep underground, in abandoned mines.LZ in an old gold mine in South Dakota and SuperCDMS in Sudbury, Canada.(Photo: SLAC).

SuperCDMS is expected to begin its search by the end of 2020 with the task of exploring the lightest WIMPs.

LZ, meanwhile, targets WIMP particles that carry heavier masses by using xenon to interact with dark matter to create electrical charges and light rays. Like SuperCDMS, LZ faces the challenge of eliminating jamming signals from radiation.

Rosenberg, a physicist from the University of Washington, is leading a project called the Axion Dark Matter Experiment G2 (ADMX G2) , which specializes in researching another dark matter candidate, Axion.

Researchers think that although these hypothetical particles are different, dark matter particles can actually be a combination of all kinds of particles.

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