The Relevance of the Dipole Penguin Operators in ${ϵ}^{\mathrm{\prime }}\mathrm{/}ϵ$

The standard model contribution to ${ϵ}^{\mathrm{\prime }}\mathrm{/}ϵ$ of the magnetic- and electric-dipole penguin operators $Q_{11} = \frac{g_s}{16\pi^2} , m_s : \bar{s}, \sigma_{\mu\nu} t^a G^{\mu\nu}a (1-\gamma_5 ), d $and$Q{12} = \frac{eQ_d}{16\pi^2}, m_s : \bar{s}, \sigma_{\mu\nu} F^{\mu\nu} (1-\gamma_5 ), d $ is discussed. While the electromagnetic penguin $Q_{12}$ seems to have a vanishingly small matrix element, we find that the gluonic dipole operator $Q_{11}$ may give a contribution to ${ϵ}^{\mathrm{\prime }}\mathrm{/}ϵ$ comparable to that of other operators so far considered, and should therefore be consistently included in the analysis.