Can a neutrino be both matter and antimatter?They don't know that, so they do it
Why do we need these experiments?
Observations by astrophysicists show that the universe is made up almost entirely of matter, even though we see almost no antimatter.Laboratory experiments and experiments at the collider show that it is possible to create both matter and antimatter in equal parts.
According to the theory, matter can be generated without antimatter in a "small bang," an ultra-rare nuclear process called neutrino-free double β decay.
Now the CUORE group has published in the journal Naturearticle about how she looked for this type of decay using isotopes of tellurium. The decay could not be detected, but the engineers were able to maintain very low temperature conditions and at the same time the instruments were very sensitive: this required stable operation of more than a ton of experimental equipment at cryogenic temperatures close to -273.149.
What did the authors study?
The object of the study was a neutrino particle.These particles are everywhere. An infinite number of neutrinos pass through one finger as a person reads this sentence. Neutrinos cannot be detected using electromagnetism or powerful strong nuclear forces. This is why particles can pass directly through a person and even the Earth.
There are a lot of neutrinos, but they are difficult to study. At the beginning of their research, physicists believed that these particles had no mass. Later it turned out that there was a mass, albeit insignificant.
But scientists still haven’t answered one question:Can a neutrino be both matter and antimatter? Each particle has an antiparticle, in other words, the same particles, only consisting of antimatter. For example, electrons have antielectrons or positrons, quarks have antiquarks, and neutrons and protons have antineutrons and antiprotons. But such an antiparticle was not found for neutrinos.
How to study neutrinos?
To understand whether neutrinos have a hypothetical antineutrino, one must try to reproduce a possible kind of radioactive decay, it is called double beta decay without neutrinos.
Beta decay itself is a common form of decay in some atoms and can convert a neutron found in the nucleus of an atom into a proton.
If we talk about double beta decay, then this isa more rare occurrence. In this case, not one neutron works, but two. During this process, they emit two electrons and two antineutrinos. So physicists want to try double beta decay without a neutrino to see if it has an antiparticle.
How was the experiment?
Researchers from the CUORE group announced in early April 2022 new results from the experiment. The authors wanted to study the nature of the neutrino.
The CUORE team works in the INFN Gran laboratorySasso, which is protected from the outside world by walls and stone 1.4 km thick. There they conducted one of the most sensitive experiments in the world to study double beta decay without neutrinos.
The results of CUORE's work are based on a hugedata set, it is 10 times larger than any other similar experiments. So far, the team has not been able to observe double beta decay without neutrinos, despite the ultra-sensitive equipment. Instead, the researchers found that, on average, it occurs in a single tellurium atom no more than once every 22 trillion trillion years. This information is very important for new discoveries in elementary particle physics.
“During any such experiments, wewe are pursuing one goal - to understand how matter formed, ”said Carlo Bucci, a researcher at the INFN Gran Sasso National Laboratory (LNGS). According to Roger Huang, a postdoctoral fellow at the Department of Energy's Lawrence Berkeley National Laboratory, scientists are looking for a process that breaks the symmetry of nature.
“If we see double beta decay without neutrinos,it will become the rarest process humans have ever recorded. Its half-life is more than a million billion times the age of the universe,” said Danielle Speller, associate professor at Johns Hopkins University and member of the CUORE Physics Council.
According to the researchers, although theyfailed to fix the long-awaited process, they are satisfied with the results of the work, in particular the technical component. The sensitivity of the detector was incredibly high: when strong earthquakes occurred in Chile and New Zealand, the researchers saw this activity on the detector. According to Laura Marini, a researcher at the Gran Sasso Institute, they could watch the waves crashing against the Adriatic Sea, 60 km from the laboratory.
How will such experiments be carried out in the future?
Based on CUORE, they are going to create the next generation of experiments. The successor to CUORE is CUPID. It is already being developed and is expected to be 10 times more sensitive than CUORE.
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