In this Figure from Wikipedia, it shows that the representations of particles of $SO(10)$ grand unified theory, representations as numbers labeled in several axes.

Descriptions: The patterns of

  • weak isospin, W,
  • weaker isospin, W',
  • strong g3 and g8,
  • baryon minus lepton, B,

charges for particles in the SO(10) model, rotated to show the embedding of the Georgi–Glashow model and Standard Model, with electric charge roughly along the vertical. In addition to Standard Model particles, the theory includes 30 colored X bosons, responsible for proton decay, and two W' bosons.


  1. There are several colors (9 colors if we try to count):
  • red, green, blue in 3 colors.
  • purple, orange, green in 3 colors.
  • yellow
  • gray
  • white

What do those colors represent? The red, green, blue should be the $SU(3)$ colors. How about other purple, orange, green in 3 colors (another Lie group)? yellow? gray? white (singlet none representation to all groups)?

  1. What distinguish the weak isospin W, and weaker isospin W'?

  2. Are there only 3 axes shown in the Figure? Are they W, W', and B? What do the Ticknumber unit 1 of the vertical axis label? (the unit of B? baryon minus lepton? or baryon?)

enter image description here


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