In a model where quarks and leptons are fermion-boson composites we show that a realistic mass spectrum and flavor mixing can be obtained in a natural way. A metacolor $\mathrm{SU}{\mathrm{}\left(n\right)\mathrm{}}_{\mathrm{MC}}$ gauge interaction, which is supposed to confine at a scale ${\Lambda }_{\mathrm{MC}}\sim 2$ TeV is responsible for the binding. The elementary fermions carry all the $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_Y\times \mathrm{SU}{\mathrm{}\left(3\right)\mathrm{}}_C$ quantum numbers, while the number $N$ of different elementary scalars determines the number of light composite families. The 't Hooft anomaly conditions impose the constraint $n=N$. The light fermions acquire their masses through transitions to quasistable excited states of mass $M\simeq {\Lambda }_{\mathrm{MC}}$, which are mediated by the $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_Y\times \mathrm{SU}{\mathrm{}\left(3\right)\mathrm{}}_C$ interactions. The neutrinos remain massless. The weak bosons $W^{\pm }$,$Z^0$ obtain their masses through the Schwinger mechanism. The main contribution to these masses comes from the coupling to the quasistable fermionic excited states. The successful lowest-order prediction of the standard model, $M_W=M_Z{cos\theta }_W$, is also obtained here. No new particles or processes that are forbidden by current phenomenology are expected.

• Received 29 December 1983

DOI:https://doi.org/10.1103/PhysRevD.30.163