A meson is composed of a quark, and an antiquark, and binding gluons.

An example is a pion of charge +1 (⁺), which is made up of an up quark and anti-down quark. The antiparticle of a meson is the quark and the antiquark reversed. For example the anti-particle of ⁺ is ^-, which is made of a down quark and an anti-up quark.

A meson is a color-neutral object, since its quark and antiquark have opposite color charges. Thus, a meson can be found in isolation. All mesons are unstable.

Since a meson has an integer spin, it is a boson. The spin is made of the spins of the quarks, plus a contribution from their motion around each other. For example notice that a pion and a rho have the same quarks, but different spins and masses.

spin=0, mass=0.14 GeV/c²

spin=1, mass =0.770 GeV/c²

Use your browser's "back" button or
go back to the Standard Model Path.