Pierre Sikivie

The spontaneous breakdown of symmetry in gauge theories is analyzed in detail for three particular choices of gauge group and Higgs representation content: the spinor and the adjoint representations of SU(n) and the (n,n) repre­sentation of SU_L(n)⊗ SU_R(n). It turns out that the subgroups which survive the spontaneous symmetry breaking as a result of the constraints of renormal1zab111ty and gauge invariance of the Higgs potential are often the ones which actually occur in particle physics: SU(2)⊗ U(l), SU(2)⊗ U(l) ⊗ U(l), SU_L(2)⊗ SU_R(2) ⊗ U(l) and SU(3) ⊗ U(l). It is pointed out that if SU(3) 1s a natural zeroth order symmetry of the quark mass-matrix, then we can find a very natural explanation cf the octet character of the SU(3) mass splittings in the second order self-energy diagrams produced by the charm-changing interactions.

A universal gauge theory of the strong, electromagnetic and weak interactions, based on the Exceptional Lie group E₆ is proposed. The theory provides us with a natural explanation of the number of colors. It does not violate parity, except through spontaneous symmetry breakdown. The existence of three charmed hadrons and two charged heavy leptons is predicted. The measured value of the Richter ratio is reproduced. A new mechanism for the suppression of ΔS = l neutral currents in six quark models is introduced, which appears to be more appropriate to the E₆ theory than the Glashow-Iliopoulos-Maiani mechanism. The corresponding effective Lagrangian is derived, and its predictions for deep inelastic neutrino scattering are worked out.