Neutrons shrink and this is good for physics

On Thursday, the researchers presented the most accurate measurement of a neutrite, reducing the maximum mass of the fantastic tracks of the material that pass through our universe.

The result, published in the journal Science, does not determine the precise mass of a neutrus, only its ceiling. But the find helps to bring physics closer to calculating exactly what is wrong with the so-called model model, the best-and incomplete-theory of laws that rule the subatomic sphere. One way that physicists know that it is not accurate enough is that it suggests that neutrino should not have a mass at all.

On the larger scales, learning more about neutrons will help cosmologists to complement the ever -cloudy image of the universe, including the way galaxies are concentrated together and what affects the expansion of the world from the Big Bang.

“We are looking to try to understand why we are here,” said John Wilkerson, a physicist at North Carolina University, Chapel Hill and author of the new study. “And this is something that neutrins may have a key role.”

Physicists know a few things about neutrons. They are productive all over the world, created almost at any time at any individual nuclei that are removed or separated. But they do not have an electric charge and are difficult to detect.

The neutrons also come in three types, which physicists describe as flavors. And, strangely, they are transformed from one taste to another as they move through space and time, a discovery recognized by the Nobel Prize in Physics in 2015.

But only so. The neutrons are slightly light and physicists do not know why.

The revelation of the precise values ​​of neutrinos mass could lead to a “gateway” in the new physics, said Alexey Lokhov, a scientist at the Karlsruhe Institute of Technology in Germany. “This is, for now, the best limit of the world,” he said of his team’s measurement.

Dr. Lokhov and his colleagues used the neutrino tritium Karlsruhe, or Katrin, to limit the mass of a neutrino. At one end of the 230 -foot length device was a third -party source, a heavier version of hydrogen with two neutrons in its core. Because the trio is unstable, it is disconnected in sun: a neutronomist turns into a proton, which spits an electron into the process. It also launches an antineutrino, the neutrino twin. The two should have identical mass.

The mass of the original third is separated between the products of the decomposition: the sun, the electron and the anti -antique. Neither neutrons nor the anti -disgusts can be detected immediately, but a sensor at the other end of the experiment has recorded 36 million electrons, over 259 days, thrown by the disconnected Trikrino. By measuring the energy of electron movement, they could indirectly conclude the maximum possible mass for antineutrino.

They found that the value does not exceed 0.45 electronics in the modules used by natural particles, one million times lighter than an electron.

The upper limit of the mass was only measured for a neutrino flavor. But Dr. Wilkerson said the nails under the mass of a one makes it possible to calculate the others.

The last measurement pushes the potential mass of neutrino lower than the previous limit set in 2022 by Katrin cooperation, no more than 0.8 electronics. It is also almost twice as expensive.

Elise Novitski, a physicist at the University of Washington, who did not participate in the project, praised Katrin’s careful effort.

“It’s really just a tour,” he said of the experiment and the discovery. “I have complete confidence in their outcome.”

The Katrin team is working on an even rigorous limit on the Neutrino mass of 1,000 days, which it expects to collect by the end of the year. This will give the physicists even more electrons for measurement, leading to a more accurate measurement.

Other experiments will also contribute to a better understanding of Neutrino’s mass, including Project 8 in Shattle and the deep underground neutrinous experiment, spreading two physics facilities in Midwest.

Astronomers studying the structure of the world in general, believed to be influenced by the huge collection of neutrinos that flood the universe have their own measurement of maximum mass of particles. However, according to Dr. Wilkerson, the boundaries set by astronomers looking out in the void do not match what particle physicists calculate in the laboratory as they look at the subatomic world.

“There’s something really interesting that is happening,” he said. “And the possible solution to this will be natural beyond the standard model.”