neutrino It is an abundant subatomic particle that plays an important role in the composition of the universe. Initially thought to be massless, these barely detectable particles should have some weight, according to the latest theory.
What exactly that measurement is has not yet been determined experimentally. An international team of scientists has come up with a new way to solve this little mystery.
Knowing the mass of neutrinos would be a huge moment for science, especially since it could help us understand how the early universe began. However, these particles did not work well with current equipment and detectors.
The answer, proposed in a new study, may lie in tracking beta decayespecially in a rare radioactive type of hydrogen called . tritium. This natural radioactive decay process can be observed, potentially revealing the weight of the neutrinos involved.
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“In principle, developing the technology and scaling it up gives us a realistic shot of reaching the range needed to pin down the mass of a neutrino.” To tell Brent Vandevender, a physicist at Pacific Northwest National Laboratory;
when tritium When it decays, it produces three elementary particles: helium ions, electrons, and neutrinos. Knowing the total mass and the masses of other particles, scientists hope that the missing mass is that of the neutrino.
This approach relies on what is known as cyclotron emission spectroscopy (CRES). microwave radiation Estimate the influence from the escaping electrons as they move along the magnetic field, and infer the influence from the accompanying neutrinos.
“Neutrinos are incredibly light” To tell Talia Weiss, a physicist at Yale University. “It is more than 500,000 times lighter than an electron. Therefore, if a neutrino and an electron are created at the same time, the neutrino’s mass has only a small effect on the electron’s motion.”
“We want to see those small effects, so we need a very accurate way to measure how fast the electrons are flying around.”
Cress is previously used Although similar experiments have been performed, the latest study is the first to analyze the beta decay of tritium and define an upper limit on neutrino mass. Additionally, while CRES is more scalable and developable than other technologies of its kind, there are still significant technical hurdles to overcome.
As the researchers point out, neutrino mass is essential in physics at all scales, including nuclear physics, particle physics, astrophysics, and cosmology. If we could weigh this particle, we might be able to tackle a whole new field of physics.
“No one else is doing this.” To tell Elise Nowitzki, a physicist at the University of Washington. “We’re not trying to take existing technology and tweak it a little bit. We’re in a sense in the Wild West.”
This study physical review letter.