Unification of the four forces in the Spin(11,1) geometric algebra

Abstract

SO(10), or equivalently its covering group Spin(10), is a well-known promising grand unified group that contains the standard-model group. The spinors of the group Spin(N) of rotations in N spacetime dimensions are indexed by a bitcode with [N/2] bits. Fermions in Spin(10) are described by five bits yzrgb, consisting of two weak bits y and z, and three colour bits r, g, b. If a sixth bit t is added, necessary to accommodate a time dimension, then the enlarged Spin(11,1) algebra contains the standard-model and Dirac algebras as commuting subalgebras, unifying the four forces. The symmetry breaking chain that breaks Spin(11,1) to the standard model appears to be essentially unique, proceeding via the Pati-Salam group. The Higgs sector appears similarly unique, consisting of the dimension~66 adjoint representation of Spin(11,1); in effect, the scalar Higgs sector matches the vector gauge sector. Although the unified algebra is that of Spin(11,1), the persistence of the electroweak Higgs field after grand symmetry breaking suggests that the gauge group before grand symmetry breaking is Spin(10,1), not the full group Spin(11,1). The running of coupling parameters predicts that the standard model should unify to the Pati-Salam group Spin(4)_w times Spin(6)_c at 10^{12} GeV, and thence to Spin(10,1) at 10^{15} GeV. The grand Higgs field breaks t-symmetry, can drive cosmological inflation, and generates a large Majorana mass for the right-handed neutrino by flipping its t-bit. The electroweak Higgs field breaks y-symmetry, and generates masses for fermions by flipping their y-bit.