The Pati Salam model seems to me the most likely to be correct.

Check it out here: http://en.wikipedia.org/wiki/Pati-Salam_model I'll
explain my reasoning.

It's not simply that you have the neutrino, up, down, and electron and
they're oriented that way. It's that you have an electron and a red
down, a blue down, and a green down. That's the SU(4). Then you have an
electron and a neutrino. That's the SU(2). The electrons can all be
replaced by neutrinos and the downs can all be replaced by ups, and the
gauge bosons that mediate the forces would remain the same.

This also does not predict proton decay unless imbedded in a higher
group. We have never found evidence of proton decay. So that's one
advantage.

If I have misinterpreted anything about this model, please tell me.
Thanks!

-Matthew Paul Finnigan-

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