Herman Verlinde and Martijn Wijnholt have been looking into the question what kind of singularity is the holographic dual to the Standard Model - more precisely, to the SSM where the missing initial "M" indicates an extended Higgs sector.
They have ended up with a dP_8 singularity (the most complicated del Pezzo surface). Their idea is that the Standard Model is everything there is - which is why it comes from a single D3-brane probing a particular singularity - and everything else is just quantum gravity encoded in the compact part of the Calabi-Yau manifold.
Today, in a
- U(3) x U(2) x U(1)7