The Standard Model of particle physics is a theory of three of the four known fundamental interactions and the elementary particles that take part in these interactions. These particles make up all visible matter in the universe.
Every high energy physics experiment carried out since the mid-20th century has eventually yielded findings consistent with the Standard Model.
Still, the Standard Model falls short of being a complete theory of fundamental interactions because it does not include gravitation, dark matter, or dark energy. It is not quite a complete description of leptons either, because it does not describe nonzero neutrino masses, although simple natural extensions do.
The particle itself is a fundamental particle and is too small to be seen by any imaginable instrument of observation. So we instead represent the property that allows the neutrino to interact.
The white area represents the weak charge of the neutrino. This charge - entirely separate from electric charge - gives rise to the Weak Nuclear Force. This force allows the neutrino to interact - but only very weakly and its typical range is much smaller than the diameter of a proton.
Neutrinos are produced when a down quark decays into an up quark, and an electron. Conservation laws require that a tiny neutral particle is created in beta decay and that particle is the neutrino (technically an anti-neutrino)
Because the neutrino only interacts through the weak force (and negligible gravity) it almost never interacts with other particles on its own. Millions of neutrinos stream through your body every second totally unnoticed and unnoticeable.
The Cassiopeia Project - making science simple!
The Cassiopeia Project is an effort to make high quality science videos available to everyone. If you can visualize it, then understanding is not far behind.