It’s nerve-wracking stuff, spending most of a decade building a huge, expensive neutrino particle detector but having to wait until it’s up and running before you know if it works. Happily for Fermilab, the NOvA detector has just recorded its first evidence of oscillating neutrinos, proving the massive investment into the 50 feet tall, 50 feet wide, and 200 feet long scientific instrument does indeed do what the team at the Fermi National Accelerator Laboratory hoped it would.
In effect, the system is one big gun for firing neutrinos and then capturing them at the other end. Fermilab creates a neutrino beam – calculating its composition at the point of origin – and then fires it in excess of 500 miles through the Earth.
At the other end, a tiny percentage of the trillions of neutrinos sent per second actually make it to the detector.
It’s what happens along the way that scientists are really interested in. The theory is that oscillations take place, changing the muon neutrinos fired out into other types – electron or tau – while in transit.
In this new research presented at the American Physical Society’s Division of Particles and Fields conference in Ann Arbor, Michigan, the scientists described how they fired many trillions of neutrinos at NOvA; had they not oscillated, the team would’ve expected to see 201 muon neutrinos reach the detector, but in fact only 33 were recorded.
Conversely, six electron neutrinos were recorded; the team had predicted only one had oscillations not occurred. Secondary analysis recorded eleven electron neutrinos.
NOvA will gather data over six years, as researchers attempt to figure out the properties of the only-vaguely-understood particles. One such question is which of the three types are the heaviest, and which the lightest; that would also help answer whether neutrinos are antiparticles in their own right or not.
Experiments to see whether neutrons are connected in some way to the Higgs Boson are also planned.
The hope is that greater understanding of subatomic physics will shed light on the building blocks of matter in our universe, including some of the fundamental constants that control matter-antimatter balance.
Update: Six, rather than eight, electron neutrinos were recorded in the first test; the story has been updated to reflect that correction, in addition to adding secondary analysis results and clarification on the number of neutrinos involved in the process.