Baryon-number dissipation at finite temperature in the standard model

We analyze the phenomenon of baryon-number violation at finite temperature in the standard model, and derive the relaxation rate for the baryon density in the high-temperature electroweak plasma. The relaxation rate {γ} is given in terms of real-time correlation functions of the operator E{·}B, and is directly proportional to the sphaleron transition rate {Γ}: {γ}{∝}nf{Γ}/T³. Hence it is not instanton suppressed, as claimed by Cohen, Dugan, and Manohar (CDM). We show explicitly how this result is consistent with the methods of CDM, once it is recognized that a new anomalous commutator is required in their approach.