Temperature Dependence of Standard Model CP Violation

TY - JOUR

T1 - Temperature Dependence of Standard Model CP Violation

AU - Brauner, T.

AU - Tannila, O.

AU - Tranberg, Anders

AU - Vuorinen, A.

PY - 2012/1/26

Y1 - 2012/1/26

N2 - We analyze the temperature dependence of CP violation effects in the standard model by determining the effective action of its bosonic fields, obtained after integrating out the fermions from the theory and performing a covariant gradient expansion. We find nonvanishing CP violating terms starting at the sixth order of the expansion, albeit only in the C-odd-P-even sector, with coefficients that depend on quark masses, Cabibbo-Kobayashi-Maskawa matrix elements, temperature and the magnitude of the Higgs field. The CP violating effects are observed to decrease rapidly with temperature, which has important implications for the generation of a matter-antimatter asymmetry in the early Universe. Our results suggest that the cold electroweak baryogenesis scenario may be viable within the standard model, provided the electroweak transition temperature is at most of order 1 GeV.

AB - We analyze the temperature dependence of CP violation effects in the standard model by determining the effective action of its bosonic fields, obtained after integrating out the fermions from the theory and performing a covariant gradient expansion. We find nonvanishing CP violating terms starting at the sixth order of the expansion, albeit only in the C-odd-P-even sector, with coefficients that depend on quark masses, Cabibbo-Kobayashi-Maskawa matrix elements, temperature and the magnitude of the Higgs field. The CP violating effects are observed to decrease rapidly with temperature, which has important implications for the generation of a matter-antimatter asymmetry in the early Universe. Our results suggest that the cold electroweak baryogenesis scenario may be viable within the standard model, provided the electroweak transition temperature is at most of order 1 GeV.

U2 - 10.1103/PhysRevLett.108.041601

DO - 10.1103/PhysRevLett.108.041601

M3 - Journal article

C2 - 22400822

SN - 0031-9007

VL - 108

SP - 041601

JO - Physical Review Letters

JF - Physical Review Letters

IS - 4

ER -