Neutrinos are known for funny business. Now scientists have set a new limit on a quantum trait responsible for the subatomic particles’ quirkiness: uncertainty.
“The ‘quantum properties of the neutrino’ stuff is a little bit of the Wild West at the moment,” says nuclear physicist Kyle Leach of Colorado School of Mines in Golden. “We’re still trying to figure it out.”
It’s impossible to know everything about a quantum particle. Heisenberg’s uncertainty principle famously states that it’s futile to attempt to precisely determine both the momentum of a quantum object and its position (SN: 1/12/22). Now, Leach and colleagues report new details about the size of the neutrino’s wave packet, which indicates the uncertainty in the particle’s position.
Quantum particles travel as waves, with ripples that are related to the probability of finding a particle at a given location. A wave packet is the set of ripples corresponding to a single particle. The new experiment sets a limit on the size of the wave packet for neutrinos produced in a particular type of radioactive decay, Leach’s team reports in a paper submitted April 3 to arXiv.org. The particles have a wave packet size of at least 6.2 trillionths of a meter.
The researchers studied neutrinos produced in the decay of beryllium-7, via a process called electron capture. In this process, a beryllium-7 nucleus absorbs an electron, and the atom transforms into lithium-7 and spits out a neutrino.
2024-05-21 08:00:00
Link from www.sciencenews.org