Brane Realization of Nambu Monopoles and Electroweak Strings

TL;DR

This paper models Nambu monopoles and electroweak strings using D-brane configurations in string theory, extending the standard model with additional Higgs fields and calculating monopole masses and binding energies.

Contribution

It introduces a novel D-brane setup to realize electroweak monopoles and strings, including composite monopoles in extended models, linking string theory to particle physics phenomena.

Findings

D-brane configurations describe electroweak strings and monopoles.

Calculated monopole mass as 689 GeV based on experimental data.

Determined binding energies of monopole composites.

Abstract

In the standard model, the electroweak Z-string can end on a Nambu monopole, whose mass is calculated to be 689 GeV from the current precise experimental data assuming the new particle with mass 125 GeV to be the Higgs boson. We study an extension of the standard model with additional singlet and triplet Higgs fields in the framework of N=1 supersymmetric field theory by using a D-brane configuration in type IIA string theory. We construct a D-brane configuration describing the electroweak symmetry breaking, and find a single D2-brane configuration describing a Z-string and a Nambu monopole attached by a Z-string in the standard model without an adjoint Higgs field. We further find a single D2-brane configuration describing a composite of a 't Hooft-Polyakov monopole and a Nambu monopole attached by a Z-string in an extended standard model with an adjoint Higgs field. We compute the binding energy of the 't Hooft-Polyakov and Nambu monopoles by solving a minimal surface area of a D2-brane.