carry normal color charges, and the signs of the Y bosons' weak isospins are always opposite the signs of their electric charges. In terms of their action on X bosons rotate between a color index and the weak isospin-up index, while Y bosons rotate between a color index and the weak isospin-down index. See also B − L Grand unification theory Leptoquark Proton decay W' and Z' bosons References Gauge bosons Hypothetical elementary particles Grand Unified Theory Force carriers Subatomic particles with spin 1