Unification of forces in Spin(11,1)

Spin(10), the covering group of SO(10), is a well-known promising grand unified group. Each of the 2⁵ = 32 spinors in a fermion multiplet of Spin(10) is actually a chiral (massless) Weyl spinor, with 2 complex components, so each fermion multiplet contains 2⁶ = 64 complex components. Weyl spinors transform under the Lorentz group Spin(3,1). It is natural to ask whether Spin(10) and Spin(3,1) might combine into a common spin group, which given that the spinor representation must have 64 components, and there must be a timelike dimension, must be the group Spin(11,1) of rotations in 11+1 spacetime dimensions. The proposed unification satisfies the Coleman-Mandula theorem, because the standard-model and Dirac algebras prove to be commuting subalgebras of the Spin(11,1) Clifford algebra. There is a unique minimal symmetry-breaking chain from Spin(11,1) to the standard model, and a unique associated minimal scalar Higgs sector that happens to match the vector gauge sector, a 66-component field in the adjoint representation. The Spin(11,1) model is highly predictive, and can and should be subjected to the battery of tests applied to other beyond-standard-model models.