Chern-Simons and winding number in a tachyonic electroweak transition

Abstract

Abstract:We investigate the development of winding number and Chern-Simons number in a tachyonic transition in the SU(2) Higgs model, motivated by the scenario of cold electroweak baryogenesis. We find that localized configurations with approximately halfinteger winding number, dubbed half-knots, play an important role in this process. When the Chern-Simons number adjusts locally to the winding number, the half-knots can stabilize and acquire half-integer Chern-Simons number as well. We present two examples from numerical simulations: one half-knot that stabilizes early and one that gives rise to a late sphaleron transition. We also study the winding number distribution after the transition and present new results on the development of the Chern-Simons susceptibility.

Cold Baryogenesis from first principles in the two-Higgs doublet model with fermions

“…In [24,25] it was argued that there is a typical physical size of the texture, deciding one or the other, and that this critical size is shifted in the presence of CP-violation. A similar behaviour was observed in [39].…”

Off-equilibrium sphaleron transitions in the glasma

“…For simplicity, we shall consider sphaleron transitions in a fixed box rather than the realistic (but computationally far more challenging) longitudinally expanding case a . We will employ a numerical lattice implementation of the classicalstatistical dynamics and adapt techniques previously developed in the context of classical Yang-Mills simulations to extract the thermal sphaleron transition rate [43][44][45][46], and in real-time studies of electroweak baryogenesis [47][48][49][50][51][52][53].…”

Simulations of Cold Electroweak Baryogenesis: quench from portal coupling to new singlet field

“…Instead of a finite temperature phase transition driven by the expansion and cooling of the Universe, symmetry breaking could instead be a spinodal transition 1 [14][15][16][17][18], triggered by the dynamics of Beyond-SM degrees of freedom. A number of realisations of this Cold Electroweak Baryogenesis scenario exist, and also a substantial body of work on computing the ensuing baryon asymmetry in different extensions of the SM [19][20][21][23][24][25][26][27][28][29][30][31].…”