Scientists have detected solar neutrinos at energies lower than ever recorded, offering a new way to study the particles produced inside the Sun. The discovery was made using XENONnT, a detector in Italy originally designed to search for dark matter.
What Are Neutrinos?
Neutrinos are extremely lightweight subatomic particles with no electric charge. They rarely interact with matter, which allows huge numbers of them to pass through Earth and even our bodies without being noticed.
A Surprising Discovery in a Dark Matter Detector
XENONnT operates at the Gran Sasso National Laboratory in Italy and was built to look for dark matter. Instead, researchers detected hundreds of neutrino-related events inside the detector.
The Lowest Energies Yet Seen
The newly detected neutrinos had energies as low as 17 kiloelectron volts, around one-tenth the energy of the least energetic neutrinos detected previously. These particles originate from the Sun’s main fusion process, in which two protons combine.
How Did Scientists Detect Them?
The neutrinos interacted with electrons inside the detector, producing tiny signals of light. Researchers then had to separate these signals from other events that could look similar. The detection reached the 5-sigma statistical benchmark, generally considered strong evidence for a discovery in particle physics.
Why the Finding Matters
Studying these low-energy neutrinos could provide scientists with another way to investigate the Sun’s interior. Researchers believe future, more advanced detectors could potentially reveal information about the Sun’s composition.
Dark Matter Research Gets an Unexpected Bonus
The discovery also demonstrates how instruments designed for one scientific purpose can contribute to another field. While XENONnT continues its search for dark matter, its sensitivity is opening new opportunities for neutrino research.
A New Window Into the Sun
Solar neutrinos offer a direct glimpse into the nuclear reactions taking place deep inside the Sun. Detecting increasingly faint and low-energy neutrinos could help scientists build a more detailed picture of our star and the fundamental particles produced within it.