The impact of LEP 2 data on possible anomalous enhancements of Re e'/e

Abstract

It has been shown in the past that the real part of the e'/e ratio is particularly sensitive to anomalous gauge couplings that modify the Standard Model Lagrangian. Due to the loose bounds on these couplings coming from low energy processes and to the poor sensitivity of hadron colliders to couplings such as $Δg_Z$, it has been argued that anomalous couplings could still produce an enhancement of Re e'/e bringing this observable closer to the experimental value obtained by KTeV, NA31 and NA48. The impact of the new measurements done at LEP2 in these years is discussed and new severe constraints to this hypothesis are determined.