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 m_s 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 m_s(m_c) = 150 ± 20 MeV and m_s(m_c) = 100 ± 20 MeV respectively. If the experimentally measured numbers and the 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 Im V_ts* V_td. Analyzing the dependence of ε′/ε on various parameters we find that only for m_s(m_c) ≤ 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.