Dynamics of Topological Defects in Electroweak Theory

Embedded defects proposed long ago (Z–vortices and Nambu monopoles) have been successfully searched for in 3D equilibrium lattice studies within the standard model near the electroweak phase transition and the crossover (which follows it for realistic Higgs mass). Gauge independent lattice–vortex operators are proposed. Vortex condensation (percolation) is found to characterize the high–temperature phase. Small vortex clusters are thermally activated with non–negligible density on the low–temperature side only at higher Higgs mass, where preliminary evidence supports their semiclassical nature.