(ORDO NEWS) — Earlier this year, decaying hydrogen isotopes gave us the smallest measurement of neutrino mass ever.
By measuring the energy distribution of the electrons released in the beta decay of tritium, physicists have determined that the upper limit for the mass of an electron antineutrino is only 0.8 electron volts.
That’s 1.6 x 10-36kg in metric weight and very, very damn small in imperial weight.
While we still don’t have precise measurements, narrowing them down brings us closer to understanding these strange particles, the role they play in the universe, and the possible impact on our current theories of physics.
The achievement was achieved in the experiment on tritium neutrinos in Karlsruhe (KATRIN) in Germany.
“The second KATRIN neutrino mass measurement campaign, presented here, achieved sub-electronvolt sensitivity,” the researchers wrote in their February 2022 paper.
“In conjunction with the first campaign, we have set an improved upper limit mν
Neutrinos are very peculiar. They are one of the most abundant subatomic particles in the universe, similar to electrons but with no charge and almost no mass.
This means that they very rarely interact with ordinary matter; in fact, there are billions going through your body right now.
All this means that measuring the near-zero mass of these particles is a particularly difficult task.
But if we can get a measurement of this property, we can learn a lot more about the universe. Unfortunately, this is also very difficult to do. You can’t just take a tiny scale and put neutrinos on it and be done.
KATRIN uses the beta decay of an unstable radioactive isotope of hydrogen called tritium to investigate the mass of neutrinos. In a 70-meter (230-foot) chamber, gaseous tritium decays into helium, an electron, and an electron antineutrino, and the results are examined by a huge sensitive spectrometer.
Since neutrinos are so ghostly, they are not. it is possible to measure them. But physicists are almost certain that a particle and its antiparticle have a uniform distribution of mass and energy; so if you measure the energy of the electrons, you can get the energy of the neutrino.
Here’s how the team arrived at the 1-electronvolt upper limit for neutrino mass back in 2019.
To refine this result, the team combined increasing the number of tritium decays with methods to reduce contamination from other types of radioactive decay, resulting in a refinement of their upper limit.
“This painstaking and complex work was the only way to eliminate the systematic error of our result due to distorting processes,” said physicists Magnus Schlösser from the Karlsruhe Institute of Technology and Susanne Mertens from the Max Planck Institute for Physics in Germany.
“We are particularly proud of our analytical team, who took on this huge challenge with great dedication and succeeded.”
The result marks the first time that neutrino measurements have fallen below the 1 electron volt threshold. This is an important result, which, although not a completely accurate mass, will allow scientists to refine the physical models of the universe.
Meanwhile, the collaboration will continue its efforts to refine measurements of the mass of the universe. neutrino.
“Further measurements of the neutrino mass will continue until the end of 2024,” the researchers said.
“In order to fully exploit the potential of this unique experiment, we will steadily increase the statistics of signal events and constantly develop and install updates to further reduce the background frequency.”
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