Attempt of solving Dark Matter mystery, made possible to see “the rarest event ever recorded”

Before going to the article, let’s know about one of the isotope of Xenon.


It has a half- life of 1.8 x 10 to the power 22 years, – roughly one trillion times longer than the age of the Universe.

Half-life of a radioisotope is the time required for half of the amount of a material to degrade into a more stable material. It often involve spitting out or capturing protons, neutrons, and electrons in various combinations.

Researchers announced that they have observed the radioactive decay of xenon-124.

Can you imagine observing a process that takes more than one trillion times longer than the age of the universe?

The evidence for xenon decay was observed as a proton inside the nucleus of a xenon atom converted into a neutron. In most elements subject to decay, that happens when one electron is pulled into the nucleus. In this case two protons within a xenon atom simultaneously absorbed two electrons, resulting in two neutrons, a special event called a double-electron capture. It only happens when two of the electrons are right next to the nucleus at just the right time described by the team as “a rare thing multiplied by another rare thing, making it ultra-rare”.

The XENON1T detector, with its low-background cryostat. It is installed in the centre of a large water shield to protect the instrument against cosmic ray backgrounds. This setup enables to greatly reduce the background noise’.
XENON1T COLLABORATION (image source- Forbes)

Thanks to XENON1T’s which was precise enough to measure the whole process. This instrument is designed to detect interactions of hypothetical dark matter particles with atoms in the 1,300 kilograms (2,866 pounds) of xenon isotope packed into the tank of the device.

The sensor captured the decay of the isotope itself, leading to a rare observation.

This is the first time to measure the half-life of this xenon isotope based on direct observation of its radioactive decay.

“It’s the longest, slowest process that has ever been directly observed, and our dark matter detector was sensitive enough to measure It.” said one of the researcher of the team, Ethan Brown from the Rensselaer Polytechnic Institute (RPI) in New York.

Article by Moumita Mazumdar

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