The Dirac equation and a non-chiral electroweak theory in six dimensional spacetime from a locally gauged SO(3,3) symmetry group

Abstract

A toy model for the electroweak interactions(without chirality) is proposed in a six dimensional spacetime with 3 timelike and 3 spacelike coordinates. The spacetime interval $ds^2=dx_\mu dx^\mu$ is left invariant under the symmetry group SO(3,3). We obtain the six-dimensional version of the Dirac gamma matrices, $\Gamma_\mu$, and write down a Dirac-like lagrangian density, ${\cal L}=i \bar{\psi} \Gamma ^\mu \nabla_\mu \psi$. The spinor $\psi$ is decomposed into two Dirac spinors, $\psi_1$ and $\psi_2$, which we interpret as the electron and neutrino fields, respectively. In six-dimensional spacetime the electron and neutrino fields are then merged in a natural manner. The SO(3,3) Lorentz symmetry group must be locally broken to the observable SO(1,3) Lorentz group, with only one observable time component, $t_z$. The $t_z$-axis may not be the same at all points of the spacetime and the effect of breaking the SO(3,3) spacetime symmetry group locally to an SO(1,3) Lorentz group is perceived by the observers as the existence of the gauge fields. The origin of mass may be attributed to the remaining two hidden timelike dimensions. We interpret the origin of mass and gauge interactions as a consequence of extra time dimensions, without the need of the so-called Higgs mechanism for the generation of mass. Further, we are able to give a geometric meaning to the electromagnetic and non-abelian gauge symmetries.