Computing the temperature dependence of effective CP violation in the standard model

Understand

CP violation in the standard model originates from the Cabibbo-Kobayashi-Maskawa mixing matrix.

• Upon integrating all fermions out of the theory, its effects are captured by a series of effective nonrenormalizable operators for the bosonic gauge and Higgs fields.
• We compute the CP-violating part of the effective action to the leading nontrivial, sixth order in the covariant gradient expansion as a function of temperature.
• In the limit of zero temperature, our result addresses the discrepancy between two independent calculations existing in the literature [1,2].