An international team of scientists has announced a breakthrough in the measurement of the mass of the neutrino , one of the elementary particles, the most abundant, but elusive, of our universe. This ad will leave you indifferent. Tomorrow will rise and you will lie down with the same worries of all the days. But where you go, unravel the mystery of these particles ghost can radically change what we know about the workings of... everything.
neutrinos are not afraid of the solid matter. Every second, trillions of them through us at the speed of light and without that we realize. Go through entire planets as they travel through space. The majority of those who come to our come from the Sun or from the atmosphere, and only a few, the higher-energy, originate further away, in clusters of galaxies. In addition to their number, their importance is enormous because the latest research has shown that they have mass and multiple identities, two phenomena that contradict the prediction of the standard model of Physics , the basic theoretical framework for understanding the cosmos.
In effect, the neutrinos should not have mass, but in 2001, two detectors, Super-Kamiokande in Japan and the Observatory of Neutrinos Sudbury, demonstrated that in reality have a non-zero, a development recognized in 2015, with the Nobel Prize in Physics.
neutrinos have mass , but how much?
experiments have set the upper limit of the mass of 2 eV. But now, the leaders of the experiment Karlsruhe Tritium Neutrino or KATRIN, famous for the spectacular pictures when it was moved in 2006 by the German city of Eggenstein-Leopoldshafen, have released new measurements that reduce the range of mass in most of the half. In particular, a decrease in the upper limit of the mass of the neutrino from 2 eV to 1 eV. The lower limit, the order of 0.02 eV, was established by previous experiments of other groups.
oh, Goodbye to the standard model?"to Know the mass of the neutrino should allow scientists to answer fundamental questions in cosmology, astrophysics and particle physics, such as how the universe evolved, or what physics exists beyond the standard model," says Hamish Robertson, scientist, KATRIN and professor emeritus of physics at the University of Washington.
even Though the neutrinos pass through matter, they are terribly elusive. Are neutral particles with no charge and interact with other matter only through the so-called "weak interaction", which means that the opportunities to detect them and measure their mass are rare and difficult. "If you would fill the solar system with lead up to fifty times beyond the orbit of Pluto, about half of the neutrinos emitted by the sun still would leave the solar system without interacting with that lead," explains Robertson.
"to Solve the mass of the neutrino would take us to brave new world to create a new standard model ," says Peter Doe, a researcher in Washington.
Neutrino-sterileThe scientists of KATRIN can not directly measure the neutrino, but they can measure the electrons that are generated by the experiment and try to calculate the properties of the neutrino in function of the electrons. A source of tritium generates around 25,000 million pairs of electrons and neutrinos per second.
With the acquisition of these data, the scientists strive now to improve even more your understanding of the mass of the neutrino. These efforts can also reveal the existence of sterile neutrinos, a possible candidate for the dark matter , even though it represents 85% of which exists in the universe, remains without being detected.
The scientists of KATRIN have established a new upper limit for the mass of the neutrino, but work to further reduce the range. "Neutrinos are tiny particles with strange -says Doe. Are ubiquitous and there is a lot that we can learn once we determine this value". Mainly, to know if there are other rules unknown that govern the universe.
Date Of Update: 22 September 2019, 00:00
