It is becoming increasingly difficult to confirm the existence of unusual neutrinos, called sterile, which hold the key to understanding dark matter, the expansion of the universe and other mysteries, but new research signals the way out of the labyrinth.
Neutrinos are mysterious quantum particles: they have mass, but very small and difficult to measure. They are surprising because the mass they contain is not contemplated in the Standard Model that describes the subatomic world.
There are three types or flavors of neutrinos: electronic, muonic, and tauonic, all experimentally proven. Scientists have long suspected that there must be a fourth type, which they have called sterile neutrinosterile neutrino, because it would never interact with anything other than another neutrino.
The sterile neutrino has not been tested experimentally, but scientists have found clear indications of its presence in the past.
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Quantum fiasco However, in 2013 the existence of sterile neutrinos was questioned because research carried out at the Max Planck Institute in Germany on the early universe found no trace of them, such as Explain in this regard the magazine Quanta.
Since then, there has been speculation with the possibility that there are not one sterile, but multiple additional neutrinos, which could interact with each other through their own secret forces, in a place in the universe that we still do not know.
Dark sector It would be like a dark sector of the quantum world formed by invisible particles that would have complicated relationships with each other, similar to those of other elementary particles, such as electrons and quarks, described in the Standard Model, adds the aforementioned journal.
This dark sector already has a own model, proposed by Janet Conrad, a physicist at the Massachusetts Institute of Technology (MIT), and Carlos Argüelles-Delgado, a neutrino physicist at Harvard University, which would include three heavy neutrinos of different masses.
It has even speculated that sterile neutrinos can disintegrate into a set of invisible particles: they would confirm the existence of the dark sector, deduced as an alternative to the impossibility of locating “intact” sterile neutrinos.
New disappointment To further complicate matters, the universities of Yale and Chicago revealed last week that four complementary analyzes developed by the international collaboration MicroBooNE, had not found traces of the sterile neutrino either. The results of these experiments are published in the arXiv repository.
And not only that, the results of this collaboration better align with the Standard Model of Particle Physics, scientists’ best theory of how the universe works, the researchers note in a release.
However, for scientists it is not a disappointment, but a finding that consolidates the idea that a dark sector is interacting from the shadow with the complex quantum universe.
Quantum whispers Quanta explains what scientists are thinking: They want to harness the whispers of known neutrinos to detect the dark sector.
That is theoretically possible because the neutrino, by itself, is already a dark particle that can interact with other imperceptible particles that have to be there, although we still don’t know how to get to them.
Although scientists are convinced of the existence of this dark sector, in constant interaction with known neutrinos, they cannot ensure that this interaction is sufficient to access the invisible particles.
Exit from the maze
Exit from the maze This speculation currently focuses one of the critical debates in particle physics, because the eventual verification of some sign of sterile neutrinos, reflected in the invisible particles that would have emerged from their disintegration, would change our understanding of the universe and clarify some of the issues. mysteries that concern us most.
Exiting this maze would be particularly important to better understand the dark matter that surrounds all galaxies, as well as to understand why the Universe contains more matter than antimatter.
That is, we would have found the core of dark matter, a type of matter that is not dark energy, or ordinary matter, or any of the three known types of neutrinos, but that occupies about 80 percent of the matter in the universe. .
historical candidates Dark matter is not made up of the usual particles, such as electrons, protons or electrons, so it has been thought that it must be made up of a particle not recognized by the Standard Model.
Sterile neutrinos have been the historical candidates to explain the composition of dark matter, so verifying that they are dominating the dark sector with invisible particles that are their direct descendants, would also explain why the universe is in an incomprehensible expansion.
References Search for an Excess of Electron Neutrino Interactions in MicroBooNE Using Multiple Final State Topologies. MicroBooNE collaboration. arXiv:2110.14054v1 [hep-ex]
Search for Neutrino-Induced Neutral Current Δ Radiative Decay in MicroBooNE and a First Test of the MiniBooNE Low Energy Excess Under a Single-Photon Hypothesis. MicroBooNE collaboration. arXiv:2110.00409v1 [hep-ex]
Top image: The IceCube neutrino detector detects energetic neutrinos that resonate through the ice below the South Pole. Credit: IceCube.
Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.