The Oscillating Neutrino
The first phase of the Booster Neutrino Experiment (BooNE) at the Fermi National Accelerator Laboratory is a smaller version of the final planned experiment, and has been dubbed "MiniBooNE." The physicists working on MiniBooNE are trying to find out more about the fundamental properties of neutrinos. But, what exactly is a neutrino? To answer that question, we need to look at what's called the Standard Model of particles and forces.
As the Elementary Particles chart at the left shows, the fundamental building blocks of the universe come in three basic categories. There are the quarks (the upper six magenta blocks), of which protons and neutrons are made; there are the leptons (the lower six grey blocks), the most familiar of which is the electron; and there are the force carriers (the four blue blocks on the right), particles responsible for mediating the basic forces between quarks and leptons. At the subatomic level, three forces play significant roles. The electromagnetic force is carried by the photon; any particle which has an electric charge will experience this force. The strong force, mediated by the gluons, holds protons and neutrons together in the atomic nucleus. The quarks, but not the leptons, feel the strong force. The weak force is conveyed by the heavy W and Z bosons; both quarks and leptons interact via the weak force.