Natural suppression of strong P- and T-invariance violations and calculable mixing angles in SU(2) x U(1)

Permutation symmetry is imposed on an SU(2)/sub L/ x U(1) x CP-invariant Lagrangian with six quarks. The mixing angles of the b and t are determined: b decays predominantly to u and a meson containing b should have a lifetime tau/sub B/ approx. = 10-11 sec or less. A phase in the gauge couplings of b and t causes nonconservation of CP in K/sub L/ decays that is naturally small. No violations of P and T invariance are induced into the strong interactions by phi < arg(DetM) at the tree level. One-loop corrections yield an upper bound of phi < 10-10(m/sub s//m/sub b/)(m/sub t//m/sub b/)2