Studying ε′/ε in the chiral quark model: γ5-scheme independence and NLO hadronic matrix elements Original Research Article

We study the CP-violating, |ΔS| = 1 parameter ε′/ε by computing the hadronic matrix elements in the chiral quark model. We estimate in the chiral expansion the coefficients of the next-to-leading order terms that correspond to the operators Q6 and Q11. We consider the impact of these corrections on the value of ε′/ε. We also investigate the possibility that the chiral quark model might drastically reduce the dimensional regularization γ5-scheme dependence of current evaluations of ε′/ε.