A 1996 analysis of the CP violating ratio ε′/ε

We update our 1993 analysis of the CP violating ratio ε′/ε in view of the changes in several input parameters, in particular the improved value of the top quark mass. We also investigate the strange quark mass ms dependence of ε′/ε in view of rather low values found in the most recent lattice calculations. A simple scanning of the input parameters within one standard deviation gives the ranges: −1.2 · 10−4 ⩽ ε′/ε ⩽ 16.0 · 10−4 and 0 ⩽ ε′/ε ⩽ 43.0 · 10−4 for ms(mc) = 150 ± 20 MeV and ms(mc) = ± 20 MeV respectively. If the experimentally measured numbers and theoretical input parameters are used with Gaussian errors, we find ε′/ε = (3.6 ± 3.4) · 10−4 and ε′/ε = (10.4 ± 8.3) · 10−4 respectively. We also give results for Vts∗Vtd. Analyzing the dependence of ε′/ε on various parameters we find that only for ms(mc) ⩽ 100 MeV and a conspiration of other input parameters, values for ε′/ε as large as (2–4) · 10−3 and consistent with the NA31 result can be obtained.