2014/04/14 by Michela D'Onofrio, Kari Rummukainen, Anders Tranberg · 2 citations
Physics and Astronomy · #hep-ph #astro-ph.CO #hep-lat
paper · pdf · doi:10.1103/physrevlett.113.141602
published as Phys. Rev. Lett. 113, 141602 (2014) · 5 pages, 3 figures
arxiv created 2014/04/14 · arxiv updated 2014/10/06
We use large-scale lattice simulations to compute the rate of baryon number violating processes (the sphaleron rate), the Higgs field expectation value, and the critical temperature in the Standard Model across the electroweak phase transition temperature. While there is no true phase transition between the high-temperature symmetric phase and the low-temperature broken phase, the cross-over is sharply defined at Tc = (159± 1) GeV. The sphaleron rate in the symmetric phase (T> Tc) is Γ/T4 = (18± 3)αW5, and in the broken phase in the physically interesting temperature range 130 GeV < T < Tc it can be parametrized as log(Γ/T4) = (0.83± 0.01)T/\rm GeV - (147.7± 1.9). The freeze-out temperature in the early Universe, where the Hubble rate wins over the baryon number violation rate, is T_* = (131.7± 2.3) GeV. These values, beyond being intrinsic properties of the Standard Model, are relevant for e.g. low-scale leptogenesis scenarios.