China’s Giant Neutrino Detector Delivers First Results With Record Precision

China’s massive Jiangmen Underground Neutrino Observatory (JUNO) has released its inaugural set of physics data, setting a new global record in measurement precision and shedding light on a decades-old puzzle in particle physics.

In findings announced Wednesday, scientists analyzed 59 days’ worth of data collected since the facility launched on Aug. 26. Their analysis produced the most precise measurements to date of two key neutrino oscillation parameters — improving on prior results by a factor of 1.5 to 1.8. The data also reaffirmed the so-called solar neutrino anomaly, a persistent discrepancy in measurements of neutrinos emitted by the sun versus those produced by nuclear reactors.

JUNO, buried 700 meters beneath the surface in Jiangmen, Guangdong province, is the first in a new wave of large-scale experiments aimed at unlocking the mysteries of neutrinos — subatomic particles so elusive they are often called “ghost particles.” The experiment is seen as a critical step toward unraveling one of the biggest unknowns in particle physics: the mass hierarchy of neutrinos. That hierarchy could hold the key to understanding why the universe contains more matter than antimatter.