Abstract
We analyze the temperature dependence of 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 violating terms starting at the sixth order of the expansion, albeit only in the -odd–-even sector, with coefficients that depend on quark masses, Cabibbo-Kobayashi-Maskawa matrix elements, temperature and the magnitude of the Higgs field. The 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.
- Received 8 November 2011
DOI:https://doi.org/10.1103/PhysRevLett.108.041601
© 2012 American Physical Society
Synopsis
Tipping the Balance
Published 26 January 2012
The breaking of charge-parity symmetry at lower temperatures than expected in the initial stages of the big bang could explain the abundance of matter over antimatter in the universe.
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