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Chern-Simons Diffusion Rate near the Electroweak Phase Transition for $m_H \approx m_W$

Jan Smit·Wai Hung Tang
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Abstract

The rate of $B$-violation in the standard model at finite temperature is closely related to the diffusion rate $Γ$ of Chern-Simons number. We compute this rate for $m_H \approx m_W$ in the classical approximation in an effective SU(2)-Higgs model, using Krasnitz's algorithm. The parameters in the effective hamiltonian are determined by comparison with dimensional reduction. In the high temperature phase we find $Γ/V (α_W T)^4 \approx 1$, neglecting a finite renormalization. In the low temperature phase near the transition we find the rate to be much larger than might be expected from previous analytic calculations based on the sphaleron.

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Jan Smit, Wai Hung Tang. 1996-05-13. Chern-Simons Diffusion Rate near the Electroweak Phase Transition for $m_H \approx m_W$. https://arxiv.org/abs/hep-lat/9605016

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