A Composite Model of Quarks with the `Effective Supersymmetry'

Abstract

We present a composite model of quarks with `effective supersymmetry'. The model is based on the gauge group $(SU(2)_S \times SU(2)_M) \times (SU(2)_U \times SU(2)_C \times SU(2)_T) \times SU(5)_{SM}$, where $SU(5)_{SM}$ is the standard model gauge group. In the dynamical supersymmetry breaking sector based on the gauge group $SU(2)_S \times SU(2)_M$, supersymmetry is dynamically broken. The preon sector is constructed by the model proposed by Nelson and Strassler. The fermion mass hierarchy among the up-type quarks originates from the $SU(2)_U \times SU(2)_C \times SU(2)_T$ gauge dynamics. The supersymmetry breaking is mediated to the minimal supersymmetric standard model sector by the `preon' superfields which compose the quarks in the first two generations. To obtain an experimentally acceptable mass spectrum, the scalar quarks in the first two generations need masses of order 10 TeV, while the other superpartners need masses less than 1 TeV. Therefore, the mass spectrum in our model is one example of the `effective supersymmetry' model proposed by Cohen, Kaplan and Nelson.