World record: Physicists put neutrinos on a scale and note an astonishingly low mass

Inhale counting zeros: there are including those before the decimal point 33: 0.00000000000000000000000000000000014 grams. The researchers recorded that record mass when they placed the neutrino, one of actually the most enigmatic building blocks, on a very precise scale. By comparison, that’s about one trillionth the mass of one coronavirus, or one millionth the mass of an electron. Never before has man been able to measure something like light so amazingly.

The new standard measurement indicates only the upper limit of the neutrino’s mass. The actual mass is still immeasurably small at the moment. The value of 0.8 eV, as the mass reads in the numerically more manageable unit “electronvolt”, used by physicists, is the absolute minimum that the experiment can still record.

The so-called Catherine Experiment was built in Germany specifically to determine the mass of neutrinos. It is not an upgraded variant of the kitchen road scale, but it does measure the mass required via a skirting. Heavy hydrogen (tritium) decays into a lighter helium nucleus and neutrinos are released.

However, these neutrinos are known to be difficult to measure, so sensors cannot capture them directly. What the experiment can do is calculate the energy of the other particles (electrons) involved in the process and derive the energy of the neutrinos from the overall energy balance. Since energy and mass are two sides of the same coin, you can also define the mass of a neutrino.

dark matter

Physicist Patrick Dekosky (Nykef), who (among other things) is looking for a neutrino mass at the competing Kamland Experiment in Japan, was excited about the results. He praised the “insanely difficult measurement” that the researchers have now successfully performed.

According to Dickowsky, the fact that the neutrino is at least a million times lighter than the electron, the lightest particle, reveals that there is something special about it. “We suspect that the neutrino is the key to many things that we don’t understand in physics right now,” he says.

For example, a particle — “or rather a neutrino-like particle we haven’t seen yet,” says Dickowsky — could be the source of the mysterious dark matter. It consists of about 85 percent of the mass in the universe, but physicists can only measure it indirectly, for example by how it attracts stars in galaxies.

It’s just one of several properties that make a particle interesting. Anyone who can determine the exact mass of a neutrino is taking an important step toward its precise properties, and thus toward a greater understanding of our reality.

“I expect more of this experience in the near future,” Dekosky says. The maximum current of 0.8 volts is already a world record, but on paper the experiment can also “weigh” a neutrino with an accuracy of 0.2 MeV. To do this, you only need to take measurements for a thousand days.