Chiral-invariant CP-violating Effective Interactions in Z Decays to three Jets
نویسنده
چکیده
Tests of CP violation by appropriate momentum correlations in Z → 3 jets and in particular in Z → bb̄X probe CP-violating effective couplings – that manifest themselves as form factors – which conserve the quark chirality and quark flavour. By giving two examples we show that such couplings can be induced at one-loop order in extensions of the Standard Model with CP violation beyond the KobayashiMaskawa phase. In one of the models we compute the chirality-conserving part of the CP-violating Zbb̄-gluon amplitude for massless b quarks, determine the resulting effective dimension d = 6 couplings in the local limit, and discuss the possible size of the effects. Finally we show that in models with excited quarks the chiral-invariant CP-violating effective interactions could be quite large if appropriate couplings are of a size characteristic of a strong interaction. 1 Research supported by BMBF, contract No. 05 6HD 93P(6) Research supported by Deutsche Forschungsgemeinschaft
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