Studies to understand the Universe are wrong, say scientists – 11/26/2021 – Science

There is something wrong with measuring the behavior of the universe’s most elusive particles, the neutrinos. According to new research, models describing the transformations that neutrinos undergo over time are out of balance, and this could seriously affect their use to understand the origins of the cosmos.

The conclusion is in an article in this week’s edition of the scientific journal Nature, one of the most important in the world.

An international team of researchers, led by Israeli Adi Ashkenazi, from Tel Aviv University, calculates that up to 70% of the interactions of neutrinos with detectors set up by scientists would have to be revised, as they do not faithfully represent what happens to the particles along the way. of its trajectory.

The changes that happen to traveling neutrinos are one of the great conundrums surrounding these ghostly particles. They are characterized by the absence of an electrical charge (hence the “neutral” that makes up their name) and by having such a small mass that it is very difficult to “weigh” them accurately.

Another difficulty has to do with the fact that neutrinos interact very little with other particles of matter – it is estimated that 100 trillion of them pass through our body every second, without any effect on the human organism (and on almost everything that exists on Earth and elsewhere in the Universe).

On these journeys, neutrinos tend to oscillate between different “flavors”, as physicists say (see infographic below).

They appear to have slightly different mass from each other and are known as electron neutrino, muon neutrino, and tau neutrino because it is these particles (electrons, muons, and taus) that are eventually detected when neutrinos interact with the nuclei of atoms. It’s as if they have a “triple personality” and alternate between one “character” and another in their path.

And this versatility is perhaps the key to understanding a process that was essential for the formation of the Cosmos as we know it. It turns out that, according to current models, the Universe should have had equal amounts of matter (such as what makes up the human body and everything that exists on Earth) and antimatter in its principles.

Antimatter is basically formed by particles similar to matter, but with a “switched signal”. Take, for example, the electron, a particle of matter that has a negative charge, while the positron, of antimatter, has a positive charge.

The problem is, when matter and antimatter meet, they destroy each other. In other words, if the baby-Universe had equal proportions of both, it would end up becoming a completely empty Cosmos.

As this did not happen, there were very likely mechanisms that caused matter to outnumber antimatter and thus survive the initial explosive encounter.

That’s where neutrinos come in. The constant transitions between “flavors” of these particles may be a clue to processes that led to the higher formation of matter in the early Universe.

But to confirm that something like this actually happened, you need to have a much clearer idea of ​​how neutrinos behave. One of the methods for this is to beam them from one laboratory to other places with detectors, separated by different distances, one greater and one less.

The increasing path makes the oscillations between the “flavors” happen gradually and be observed.

The problem is that, due to the very spooky nature of neutrinos, all this happens indirectly, when they bump into the nuclei of atoms and produce other particles.

To better understand how the process happens, the new research, led by Adi Ashkenazi, used another particle, the electron, whose behavior is far more understood and easier to measure and, moreover, can be described mathematically in a similar way to that of neutrinos.

Using this method, the team found that the models used to reconstruct the behavior of the neutrinos appear to be quite inaccurate, being unable to produce reliable data about the electrons (in this case, since it was possible to measure the electrons directly, it was relatively easy to check the accuracy. models).

“These results, therefore, indicate the need for a substantial improvement in the precision with which the neutrino interactions are modelled”, says Noemi Rocco, from the Fermi National Accelerator Laboratory (USA), who commented on the study on neutrinos at the request of Nature.

Without this improvement, runaway particles will not be enough to revolutionize knowledge about the origins of the Universe.

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