Monopoles in lattice Electroweak theory

TL;DR

This study uses lattice numerical methods to explore monopole-like topological defects in Electroweak theory, revealing that monopole density is an independent parameter and examining differences between gauge group versions.

Contribution

It demonstrates that monopole density acts as a new external parameter in Electroweak theory and compares different gauge group formulations using lattice simulations.

Findings

Monopole density cannot be predicted by initial parameters.

No difference detected between gauge groups at physical coupling.

Differences emerge at unphysical large coupling constants.

Abstract

There exist several types of monopole - like topological defects in Electroweak theory. We investigate properties of these objects using lattice numerical methods. The intimate connection between them and the dynamics of the theory is established. We find that the density of Nambu monopoles cannot be predicted by the choice of the initial parameters of Electroweak theory and should be considered as the new external parameter of the theory. We also investigate the difference between the versions of Electroweak theory with the gauge groups $SU(2)\otimes U(1)$ and $SU(2)\otimes U(1)/Z_2$. We do not detect any difference at $\alpha \sim {1/128}$. However, such a difference appears in the unphysical region of large coupling constant $\alpha > 0.1$.