Standard-model Dirac particles trapped in flat (noncompact) higher dimensions

We show that if the field equation for a Dirac particle is extended to (7 1) flat dimensions, and a harmonic oscillator potential and a large consta nt are introduced in the four extra dimensions (R) over tilde(4) to confine the particle, then "orbital" times "spin" solutions are generated in (R) o ver tilde(4) which exhibit approximate SU(4) x SU(2) symmetry. We show that these representations bear some resemblance to quarks and leptons.