Tuesday , May 11 2021

The dark matter detectors records extremely rare decay of Xanon 124


Researchers just measured an atom with a half-life of 18 sextillion years

This new discovery of the second most rare decomposition process in the universe does not bring the xenon team closer to finding dark matter, but it proves the versatility of the detector. Now, a global team of scientists, including researchers at the University of California at San Diego, report in the journal Nature that they have seen the decay of these ancient atoms for the first time. The half-life measured for XENON 124 by the XENON1T detector has the greatest value of 1.8 × 1022 years for this process: approximately 1 trillion times greater than the age of the universe, making the radioactive measured double electron decay of xenon the most rare process observed – Once in the detector. However, to date no evidence has emerged for this process. While two neutrinos have been emitted in the double process of electrons, scientists can now also search for the so-called "neutering", which captured the double electron, which can shed light on important questions about nature Of neutrinos.

How do you observe a process that takes more than a trillion times the age of the universe? "This is the longest and slowest process to be observed immediately, and our dark matter detector was sensitive enough to measure it," said Ethan Brown, associate professor and professor of physics at the Rensselaer Polytechnic Institute, in a report from the University.

Brown called it "the most rare thing ever recorded".

This is a wonderful achievement, because the decay of this isotope is very slow.

XENON's collaboration works with XENON1T, which is 1,300 km of value-added pure supercellular xenon shielded from the cosmic rays in the Cryostat, which is immersed in water 1,500 meters below the Gran Sasso Mountains in Italy. "Basically, such a sensitive detector allows us to do all Kinds of cool physical measurements that are not accessible in any other way. "

"We've seen this rot happening, the number simply indicates how long, on average, the lion's share of radioactive material will be reduced to half by half," said Dr. Christopher Tunnell, a physicist at Rice University and a member of XENON's Collaboration. The interaction between the dark matter particle and the nucleus of a xenon atom, a detector that actually picks up signals from any interaction with xenon.

This great achievement marks the first time that experts have measured half the life of this xenon isotope, based on direct observation of radioactive decay.

Brown is one of several scientists working on the collaboration of XENON, who runs the XENON1T experiment. "In addition, it shows that if someone can detect dark matter, it must be us!". "We measure them with the light sensors and reconstruct everything we can about the original event that caused the light and the charge."

"Because dark matter collisions and xenon-124 anxieties are so rare, we need to have the cleanest environment imaginable, so we use very clean materials and operate the detector deep below the mountains to evade cosmic rays and other backgrounds," he said. . . "Then we monitor a huge volume of xenon as long as we can try to see these rare events." This is when the proton inside the nucleus of a xenon atom converts into neutrons. Two protons must capture two electrons to become a neutron.

But along with the standard xenon, the detector contains traces of a rare isotope known as XE-124, whose atoms are likely to be stable and capable of triggering their signals.

It can only happen when two electrons are right next to the nucleus just at the right time – "a rare thing is multiplied another rare thing, making it ultra rare," Brown said in a statement. To prove that an event of two neutrinos for electron capture occurred, the researchers instead of Xenon examined the empty spaces left behind in a crumbling atom. Researchers are looking for dark matter (which is five times more abundant than ordinary matter, but rarely interacts with ordinary matter) by recording tiny flashes of light generated when nanoparticles interact with xenon inside the detector.

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