 SU(5) grand unified theory

An SU(5) grand unified theory embeds $SU(3{)}_c\times SU(2{)}_L\times U(1{)}_Y$ into $SU(5)$. Canonical normalization of its hypercharge generator predicts $g_s^2=g_w^2=(5/3)g_Y^2$ at the unification scale.