A Realistic Supersymmetric Model with Composite Quarks

Abstract

We describe a realistic, renormalizable, supersymmetric ``quindecuplet'' model in which the top quark, left handed bottom quark, and up-type Higgs boson are composite, with a compositeness scale $\sim 1-3$ TeV. The top-Higgs Yukawa coupling is a dynamically generated strong interaction effect, and is naturally much larger than any other Yukawa coupling. The light quark doublets and right-handed up-type quarks are also composite but at higher energies; the hierarchy of quark masses and mixings is due to a hierarchy in the compositeness scales. Flavor changing neutral currents are naturally suppressed, as is baryon number violation by Planck-scale dimension five operators. The model predicts that the most easily observable effects would be on $b$-quark physics and on the $\rho$ parameter. In particular a small negative $\Delta\rho=-\epsilon$ leads to $\Delta R_b> +2\epsilon$. There are effects on $B$ meson mixing and on flavor-changing neutral-current $b$-quark decays to leptons which might be detectable, but not on $b\rightarrow s\gamma$. The model also suggests the supersymmetry-breaking mass for the right handed top squark might be considerably larger than that of the left handed top squark.