Faint flashes of light may soon reveal more about some of nature’s most ghostly particles — and maybe even new clues to an enduring mystery about the universe. A pair of neutrino detectors now up and running beneath a mountain in China, part of the Daya Bay Reactor Neutrino Experiment, count antineutrinos shooting out of nearby nuclear reactors.
Antineutrinos, neutral particles that hardly interact with matter, come in three different types (electron, tau or muon) and can change, or oscillate, from one type to another while traveling through space.
By comparing counts from this pair of detectors to counts from other detectors farther from the reactors, the new experiment will measure how often electron antineutrinos disappear as the particles change form. Physicists hope to estimate a parameter to within one percent certainty called theta one-three (θ13) that governs the shape-shifting behavior of electron antineutrinos.
Ultimately, understanding neutrino and antineutrino oscillations could help explain why the universe contains vastly more matter than antimatter.