Supersymmetric corrections to $\epsilon^\prime /\epsilon at the leading order in QCD and QED

Abstract

We study the corrections to $\epsilon^\prime /\epsilon$ in the minimal supersymmetric model at the leading order in QCD and QED. Supersymmetry can increase the standard model prediction for $\epsilon^\prime /\epsilon$ by at most 40\% for $m_t=174$ GeV, an enhancement which is indistinguishable from the present theoretical uncertainties. The most conspicuous effect of supersymmetry is a strong depletion of $\epsilon^\prime /\epsilon$. For certain choices of supersymmetric parameters, vanishing and even small negative values of $\epsilon^\prime /\epsilon$ can be obtained for the top quark in the CDF range.