On Thursday, researchers revealed the most precise measurement to now of a neutrino, whereby they shot the maximum possible mass of the speckles of matter that penetrate our universe.
The result, published in the Journal Science, does not define the exact mass of a neutrino, only the upper limit. But the finding helps physicists closer to figure out exactly what is wrong with the so-called standard model, their best-to-side the incomplete theory of the laws that rule the subatomic empire. A way in which physicists know that it is not completely accurate is that it suggests that the neutrino should not have a mass at all.
On Grander Scales will learn more about Neutrin's cosmologists to fill their always blurry image of the universe, including how galaxies are merged and what the expansion of the cosmos has influenced since the big bang.
“We try to understand why we are here,” says John Wilkerson, a physicist at the University of North Carolina, Chapel Hill and an author of the new study. “And that is something that Neutrinos can play a key role.”
Physicists know a few things about neutrinos. They are productive in the cosmos, which are created almost at any time, atomic cores understand together or cracks. But they have no electrical charge and are notorously difficult to detect.
Neutrinos are also in three types that physicists describe as flavors. And strangely enough, they change from one taste to another while moving through space and time, a discovery that is recognized in 2015 by the Nobel Prize in Physics. The underlying mechanism that makes these transformations possible, realized physicists, meant that neutrinos should have some mass.
But just like that. Neutrinos are stunning light and physicists don't know why.
Discovering the exact values of the mass neutrinos could lead to “a kind of portal” for new physics, said Alexey Lokhov, a scientist at the Karlsruhe Institute of Technology in Germany. “This is the best limit in the world for the time being,” he said about the measurement of his team.
Dr. Lokhov and his colleagues used the Karlsruhe Tritium -Neutino or Katrin, experimenting to limit the mass of a neutrino. At one end of the 230-foot long device was a source of tritium, a heavier version of hydrogen with two neutrons in its core. Because tritium is unstable, it canceled in helium: one neutrons turns into a proton that spits an electron out in the process. It also spits an antineutrino, the antimatter twins of a neutrino. The two should have identical mass.
The mass of the original tritium is spread over the products of the decay: the helium, electron and antineutrino. Neutrinos nor antineutinos can be detected directly, but a sensor on the other side of the experiment registered 36 million electrons, for 259 days, thrown by the rotting tritium. By measuring the energy of the electron movement, they can indirectly distract the maximum mass that is possible for the Antineutrino.
They discovered that value was no more than 0.45 electron fillets, in the masses used by particle physicists, one million times lighter than an electron.
The upper limit on the mass was measured for just one taste of neutrino. But Dr. Wilkerson said that the mass of one makes it possible to calculate the rest.
The newest measurement pushes the possible mass of the neutrino lower than the previous limit in 2022 through the collaboration between Katrin, of no more than 0.8 electron fillets. It is also almost twice as accurate.
Elise Novitski, a physicist at the University of Washington who was not involved in the work, praised the careful efforts of the Katrin team.
“It's just a Tour de Force,” she said about the experiment and the discovery. “I have full faith in their result.”
The Katrin team works on an even tighter border on the neutrinomass of 1000 days of data, which expected to collect at the end of the year. That gives the physicists even more electrons to measure, which leads to a more precise measurement.
Other experiments will also contribute to a better understanding of the mass of the neutrino, including project 8 in Seattle and the deep underground neutrino experiment, spread over two physics facilities in the midwest.
Astronomers that generally study the structure of the cosmos, which are thought to be influenced by the enormous collection of neutrinos that flood the universe have their own measurement of the maximum mass of the particles. But according to Dr. Wilkerson do not correspond to the boundaries of astronomers that stare in the void with what particle physicists in the lab calculate while investigating the subatomic world.
“Something very interesting is going on,” he said. “And the likely solution for that will be physics outside the standard model.”
