W and Z bosons weak-force boson particle. Thus, this interaction requires a Z boson. These bosons are among the heavyweights of the elementary particles. With masses of and , respectively, the W and Z bosons are almost 80 times as massive as the proton – heavier, even, than entire iron atoms. Their high masses limit the range of the weak interaction. By way of contrast, the photon is the force carrier of the electromagnetic force and has zero mass, consistent with the infinite range of electromagnetism; the hypothetical graviton is also expected to have zero mass. (Although gluons are also presumed to have zero
Generation (particle physics) Generation (particle physics) In particle physics, a generation or family is a division of the elementary particles. Between generations, particles differ by their flavour quantum number and mass, but their interactions are identical. There are three generations according to the Standard Model of particle physics. Each generation is divided into two types of leptons and two types of quarks. The two leptons may be classified into one with electric charge −1 (electron-like) and one neutral (neutrino); the two quarks may be classified into one with charge − (down-type) and one with charge + (up-type). The basic features of quark-lepton generation