Elementary particle the fact that multiple bosons can occupy the same quantum state (Pauli exclusion principle). Also, bosons can be either elementary, like photons, or a combination, like mesons. The spin of bosons are integers instead of half integers. Gluons mediate the strong interaction, which join quarks and thereby form hadrons, which are either baryons (three quarks) or mesons (one quark and one antiquark). Protons and neutrons are baryons, joined by gluons to form the atomic nucleus. Like quarks, gluons exhibit color and anticolor—unrelated to the concept of visual color—sometimes in combinations, altogether eight variations of gluons. There are three weak gauge
W and Z bosons particles, starting with and , all denote quarks and antiquarks (factor "N" is applied). The various "V" denote the corresponding CKM matrix coefficients. Unitarity of the CKM matrix implies that Z bosons decay into a fermion and its antiparticle. As the Z boson is a mixture of the pre-symmetry-breaking W and B bosons (see weak mixing angle), each vertex factor includes a factor "T" − "Q" sin"θ" where "T" is the third component of the weak isospin of the fermion, "Q "is the electric charge of the fermion (in units of the elementary charge), and "θ" is the weak mixing