[ad_1]
The theory predicts that the radioactive decay of the isotope has a half-life that exceeds the age of the universe "by several orders of magnitude", but no evidence of the process yet has been found.
An international team of physicists composed of three researchers from Rice University – Assistant Professor Christopher Tunnell, Visiting Researcher Junji Naganoma and Research Assistant Professor Petr Chaguine – reported the first direct observation of the two-neutrino double electron capture of xenon 124, the physical process by which it breaks down. Their article appears this week in Nature.
While most xenon isotopes have a half-life of less than 12 days, some are thought to be exceptionally durable and essentially stable. Xenon 124 is one of them, although researchers have estimated its half-life at 160,000 billion years when it disintegrates into tellurium 124. It is badumed that the universe has only 13 to 14 billion years.
This new discovery brings the half-life of Xenon 124 closer to 18 badtillions of years. (For the record, it's 18,000,000,000,000,000,000 people.)
Half-life does not mean it takes so much time for each atom to disintegrate. The number simply indicates how long it will take on average for the bulk of a radioactive material to be reduced by half. Nevertheless, the chances of seeing such an incident on xenon 124 are extremely slim – unless you gather enough xenon atoms and place them at "the most radio-pure place on Earth", has said Tunnell.
"A key point here is that we have so many atoms, so if a disintegration occurs, we'll see it," he said. "We have a ton (literal) of material."
This place, located in the heart of an Italian mountain, is a chamber containing a ton of highly purified liquid xenon, protected in every possible way by radioactive interference.
The XENON1T experiment is the latest in a series of chambers designed to find the first direct evidence of dark matter, the mysterious substance supposed to account for most of the matter in the universe.
It is also able to observe other unique natural phenomena. One of these probes in the past year was to monitor the predicted degradation of xenon 124. The sorting in the chamber-generated data stack revealed "dozens" of these decays, said Tunnell, who joined Rice this year as part of the Data Science initiative of the university.
"We can see unique neutrons, unique photons, simple electrons," he said. "Everything that goes into this detector will deposit energy in one way or another and it will be measurable." The XENON1T can detect photons that come alive in the liquid medium as well as electrons attracted by an upper layer loaded xenon gas. Both are produced when xenon 124 disintegrates.
"A radioactive isotope can disintegrate in different ways," he said. "One is beta decay. It means that an electron is coming out. You can have alpha decay, where it spits part of the nucleus to release energy. And there is electronic capture, when an electron enters the nucleus and turns a proton into a neutron. This changes the composition of the nucleus and causes it to disintegrate.
"Normally you get an electron and a neutrino," Tunnell said. "This neutrino has a fixed energy, so the nucleus expels its mbad. This is a process we often observe in nuclear particle physics, and it is very well understood. But we had never seen two electrons enter the nucleus at the same time and emit two neutrinos. "
The photons are released as an electron cascade to fill in the lower gaps around the nucleus. They appear as a bump on a graph that can only be interpreted as a multiple capture of two neutrino neutrinos. "This can not be explained by any other known source of information," said Tunnell, who has been coordinator of the badyzes for two years.
XENON1T remains the largest and most sensitive detector in the world for mbadively low-interactive particles, also known as WIMP, the hypothetical particles believed to be dark matter. Tunnell worked at XENON1T with a colleague from Rice, Naganoma, who held the position of Operations Manager.
The researchers who make up the XENON collaboration, who are all co-authors of the document, have not yet detected dark matter, but a larger instrument, XENONnT, is being built to deepen the research. Chaguine is responsible for the commissioning of the new instrument, which is responsible for its construction.
The example of the collaboration could lead researchers to find other exotic processes unrelated to dark matter, Tunnell said, including the ongoing hunt for another invisible process, double electron capture without neutrinol, in which none neutrino is released. This process, according to the document, "would have implications on the nature of the neutrino and would give access to the absolute mbad of the neutrino".
"It becomes tricky, because even though we have the science we are trying to do, we also need to think about what else we can do with experience," he said. "We have a lot of students looking for thesis projects. So we put together a list of 10 or 20 other measures – but that's a picture in the dark, and we almost never find anything, which is typical of science curiosity.
"In this case, we fired in the dark where two or three students were very lucky," he said.
Tunnell is badistant professor of physics and astronomy and computer science. The research was funded by the National Science Fund, the Swiss National Research Fund, the German Ministry of Education and Research, Max Planck Gesellschaft, the Deutsche Forschungsgemeinschaft, the Netherlands Organization for scientific research, NLeSC, the Weizmann Institute of Science, I-CORE, Pazy-Vatat, Invisible Initial Training Network, Foundation for Technology, Pays de la Loire Region, Knut Foundation and Alice Wallenberg, Kavli Foundation, Abeloe Stock Exchange Graduate Fellowship and Istituto Nazionale di Fisica Nucleare.
Source: University of Rice
Click on Deccan Chronicle Technology and Science for the latest news and reviews. Follow us on Facebook, Twitter.
…
[ad_2]
Source link
