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The study of the subatomic world has revolutionized our understanding of the laws of the universe and given humanity unprecedented knowledge on profound issues. Historically, these questions have been in the philosophical realm: how was the universe born? Why is the universe such as it is? Why is there something instead of nothing?
Well, pass the philosophy because science has taken a crucial step in the construction of equipment that will help us answer such questions. And that involves drawing ghostly particles called neutrinos across the Earth over a distance of nearly 1,300 kilometers from one physics lab to another.
An international group of physicists said they saw the first signals in a cube-shaped detector called ProtoDUNE. This is a very important step in the DUNE experiment, which will be America's flagship research program in particle physics for the next two decades. ProtoDUNE, which is the size of a three story home, is a prototype of the much larger detectors that will be used in the DUNE experience and today 's announcement ( September 18) demonstrates that the selected technology works. [The 18 Biggest Unsolved Mysteries in Physics]
The DUNE detectors will be located at Fermilab's National Accelerator Laboratory (Fermilab), just outside of Chicago, and at the Sanford Underground Research Facility (SURF) in Lead, South Dakota. When the experiment is operational, a powerful Fermilab particle accelerator will produce an intense beam of subatomic particles called neutrinos, which will propel them literally across the Earth to be detected at SURF.
Neutrinos are the ghosts of the subatomic world, able to cross the entire planet with almost no interaction. Neutrinos have surprised scientists many times in the past. From their unprecedented ability to pass the material without interacting, to the very different treatment of matter and antimatter, to their ability to switch from one version to another, neutrinos continue to fascinate the community. world scientist. These are the last two properties that the DUNE experiment will study.
The antimatter looks like science fiction, but it is definitely real. Antimatter is the opposite of matter; Gather matter and antimatter and they will wipe out pure energy. Antimatter was first proposed in 1928 and observed for the first time in 1931. In the decades that followed, scientists (including myself) studied it in extremely difficult details. Most of the time, it is understood, with a mystery that remains very frustrating. When we convert energy into antimatter, we produce an identical amount of matter. It is a well-established science. This is not the problem.
The problem is that if we combine this observation with the idea of the Big Bang, something is wrong together. After all, soon after the Big Bang, the universe was full of energy, which should have turned into matter and antimatter equally. Yet our universe is made up entirely of matter. So where did this antimatter go? This question is unanswered; but perhaps a careful study of the neutrinos of matter and antimatter could reveal a difference. [Big Bang to Civilization 10 Amazing Origin Events]
Like other subatomic particles, neutrinos and antimatter neutrinos, called antineutrinos, have a quantity called spin, which looks like a small, spinning ball, although imperfect. Neutrinos and antineutrinos turn in opposite directions. If you shoot a neutrino beam so that it comes to you, you can look at the axis of rotation of neutrinos. you will see them turn clockwise, while the antineutrinos turn in the opposite direction. Because the spin of neutrinos and antineutrinos is the opposite, it identifies a difference between the two. Perhaps this difference is a sign that the study of neutrino matter and antimatter analogues will illuminate this mystery.
There is another property of neutrinos that makes them interesting in the puzzle of the absence of antimatter … they can turn from one identity to another. Scientists have found three distinct types of neutrinos. One type is associated with electrons and is called electron neutrinos. The other two are associated with two other subatomic particles called muon and tau, which are heavy cousins of the electron.
If you start with a bunch of electronic neutrinos and look at them a little later, you will find that there are fewer electronic neutrinos than you have at the start, but the deficit is enough to offset the deficit. Neutrinos do not decompose; they transform each other.
It's as if you had a room full of 100 dogs and, when you looked later, there were 80 dogs, 17 cats and three parrots. If you look again later, the mix would be different again.
Morphing, which scientists call the oscillation of neutrinos, is also a well-established physics. Researchers have suspected it since the 1960s; they were pretty much certain that it was real in 1998 and they were successful in 2001. The neutrino oscillation occurs and his discovery was awarded the Nobel Prize in Physics 2015.
The DUNE experiment has several research objectives, but the most urgent is perhaps to first measure the oscillation of neutrinos, then the oscillation of antineutrinos. If they are different, it may be that understanding this process helps us understand why the universe is only made up of matter. In short, it could explain why we exist at all.
The DUNE experiment will consist of two detector complexes, a smaller one at Fermilab and four larger ones located at SURF. A neutrino beam will leave the laboratory and go to the remote detectors. The proportions of the different types of neutrinos will be measured at the Fermilab and SURF detectors. Differences caused by neutrino oscillation will be measured, then the process will be repeated for antineutrinos.
The technology that will be used in the DUNE experiments involves large liquid argon tanks, in which the neutrinos will interact and be detected. Each of the largest detectors located at SURF will be as large and wide as a four-story building and longer than a football field. Each will contain 17,000 tons of liquid argon.
The ProtoDUNE detector is a much smaller prototype, consisting of only 800 tons of liquid argon. The volume is large enough to encompass a small house.
The collaboration of DUNE scientists is global, attracting researchers from around the world. While Fermilab is the host laboratory, other international labs are also involved. CERN, the European particle physics laboratory located just outside Geneva, Switzerland, is one of these facilities. The ProtoDUNE detector is located at CERN, further strengthening the long-standing relationship between laboratories – for example, Fermilab has long been involved in research using data recorded by CERN's Large Hadron Collider. DUNE is CERN's first investment in a laboratory experiment in the United States.
Today's announcement is a great one, proving that the liquid argon technology that will be the heart of the DUNE experiment was a good choice. A second ProtoDUNE detector will be online in a few months. The second version uses a slightly different technology to observe particle tracks caused by rare interactions between neutrinos. The results of the tests of these two detectors will guide the scientists towards a decision on the final design of the detector components.
DUNE will be built in the next decade and the first detection modules should be operational in 2026.
Originally published on Live Science.
Don Lincoln is a physics researcher at Fermilab. He is the author of "The Large Hadron Collider: The Extraordinary History of the Higgs Boson and other things that will delight you" (Johns Hopkins University Press, 2014) and he produces a series of videos on science education.. Follow him on Facebook. The opinions expressed in this comment are his.
Don Lincoln contributed this article to the expertise of Live Science: Op-Ed & Insights.
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