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Weinberg CP -violation model revisited

1986; American Physical Society; Volume: 34; Issue: 5 Linguagem: Inglês

10.1103/physrevd.34.1397

1538-4500

Hai-Yang Cheng,

High-Energy Particle Collisions Research

Chiral properties of the weak amplitudes in the Weinberg model of CP violation are carefully treated. The CP-odd K\ensuremath{\rightarrow}2\ensuremath{\pi} amplitude is chiral-symmetry nonlinear-realization dependent, and so is the soft-pion relation. This realization dependence is canceled by the pole contribution arising from the combination of a strong K\ensuremath{\pi} vertex and a K-vacuum tadpole, so that to lowest order in chiral symmetry the physical K\ensuremath{\rightarrow}2\ensuremath{\pi} amplitude is chiral-model independent. The vacuum-insertion method is valid only in a particular realization scheme. Various CP-violating effects are then reexamined in this model. When the \ensuremath{\eta}-\ensuremath{\eta}' mixing is taken into account, \ensuremath{\epsilon}'/\ensuremath{\epsilon}\ensuremath{\approxeq}-0.007 is obtained. The electric dipole moment of a neutron due to neutral-Higgs-boson exchange and the current experimental limit are used to set an upper bound for neutral-Higgs-boson mixing. Finally, CP violation in K\ensuremath{\rightarrow}3\ensuremath{\pi} decays is discussed.