neutrino

Any of three electrically neutral leptons (the electron neutrino, muon neutrino and tau neutrino—one in each of the three generations of elementary fermions) that have small or very small masses.

An elementary particle that is classified as a lepton, and has an extremely small but nonzero mass and no electric charge. It interacts with the surroundings only via the weak force or gravitation, making it very difficult to detect.

an elementary particle with zero charge and zero mass