The puzzle of neutrinos, seventy years on – Home

Seventy years ago, physicists Clyde Cowan and Frederick Reines confirmed the existence of the neutrino. This breakthrough validated a theory proposed by Wolfgang Pauli in 1930. Pauli suggested that a neutral, lightweight particle was responsible for the energy appearing to vanish during beta decay processes. This discovery marked the end of a twenty-five-year search and reshaped how we understand the building blocks of matter.

Neutrinos remain some of the most mysterious particles in physics. They lack electric charge and interact so weakly with matter that they travel through solid lead with ease. While we know they exist, they still present major questions. Scientists now know these particles oscillate between three distinct types. This behavior proves they possess mass, a fact that challenged the original Standard Model of particle physics.

Research continues to push boundaries across the globe. Projects like the Jiangmen Underground Neutrino Observatory in China and the Deep Underground Neutrino Experiment in the United States aim to measure neutrino mass and observe how these particles behave over long distances. The data collected from these experiments may reveal how matter clustered to form galaxies in the early universe.

Modern physicists look toward neutrino tagging to improve experimental precision. By measuring the parent particle and the resulting muon during decay, researchers can determine the energy and momentum of individual neutrinos. Recent work at the NA62 experiment at CERN demonstrates how this technique tracks billions of particles to pinpoint energy with high accuracy. This precise data provides a foundation for the next generation of particle physics research.