Yukawa enhancement of Z-mediated new physics in ∆S = 2 and ∆B = 2 processes

We discuss Yukawa-enhanced contributions from Z-mediated new physics to down-type quark Delta F = 2 processes in the framework of the standard model gaugeinvariant effective theory (SMEFT). Besides the renormalization group (RG) mixing of the Z-mediating psi(HD)-H-2-D-2 operators into Delta F = 2 operators, we include at the electroweak scale one-loop (NLO) matching corrections consistently, necessary for the removal of the matching scale dependence. We point out that the right-handed Z-mediated interactions generate through Yukawa RG mixing Delta F = 2 left-right operators, which are further enhanced through QCD RG effects and chirally enhanced hadronic matrix elements. We investigate the impact of these new effects on the known correlations between Delta F = 2 and Delta F = 1 transitions in the SMEFT framework and point out qualitative differences to previous parameterizations of Z-mediated new physics that arise for the left-handed case. We illustrate how specific models fit into our model-independent framework by using four models with vector-like quarks. We carry out model-independent analyses of scenarios with purely left-handed and purely right-handed new-physics Z couplings for each of the three sectors s -> d, b -> s and b -> d. Specifically we discuss the correlations between epsilon'/epsilon, epsilon(K), K-L -> mu(+)mu(-) K+ -> pi(+)nu(nu) over bar and K-L -> pi(0)nu(nu) over bar in the Kaon sector, and phi(s), B-s -> mu(+)mu(-) and B -> K-(*())(mu(+)mu(-), nu(nu) over bar) in the b -> s sector and B-d -> mu(+)mu(-) in the b -> d sector.