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

Abstract

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]. We find that CP violation in the standard model is strongly suppressed at high temperature, but that at T<1GeV it may be relevant for certain scenarios of baryogenesis. We also identify a selected class of operators at the next, eighth order and discuss the convergence of the covariant gradient expansion.

34 pages, 5 eps figures, jheppub style; v2: minor corrections, published version

References in corpus (5)

• Sizable CP Violation in the Bosonized Standard Model
• Simulations of Cold Electroweak Baryogenesis: Dependence on Higgs mass and strength of CP-violation
• CP violation in the effective action of the Standard Model
• Leading order one-loop CP and P violating effective action in the Standard Model
• Possibility of Electroweak Phase Transition at Low Temperature