According to the principle of minimality, we find a new SU(6) model. T
his SU(6) model, and other models, can be identified as a theoretical
origin of an extra Z0 boson. We apply the strategy of Boudjema et al.
(BLRV) which is very effective in identifying the theoretical origin o
f an extra Z0 boson in the new SU(6) model, and compare the model with
six other models.