The Central Correlations of Hypercharge, Isospin, Colour and Chirality   in the Standard Model
  The correlation of the fractionally represented hypercharge group with the isospin and colour group in the standard model determines as faithfully represented internal group the quotient group ${\U(1)\x\SU(2)\x\SU(3)\over\Z_2\x\Z_3}$. The discrete cyclic central abelian-nonabelian internal correlation involved is considered with respect to its consequences for the representations by the standard model fields, the electroweak mixing angle and the symmetry breakdown. There exists a further discrete $\Z_2$-correlation between chirality and Lorentz properties and also a continuous $\U(1)$-external-internal one between hyperisospin and chirality. 
Heinrich Saller (MPI f. Physik)