Stable Z-strings with topological polarization in two Higgs doublet model

Minoru Eto, Yu Hamada, Muneto Nitta

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


We find that a Z-string is stable in a wide range of parameter space of the two Higgs doublet model due to a split into a pair of two topological Z-strings with fractional Z fluxes. This configuration, a bound state of the two strings connected by a domain wall, is called a vortex molecule. Although the vortex molecule has no net topological charge, the locally induced topological charge density is polarized, namely distributed positively around one constituent string and negatively around the other constituent string, leading to the stability of the molecule. We numerically show that the vortex molecule is indeed a stable solution of the equation of motions in a much wider parameter space of the model than the usual axially symmetric Z-string in the Standard Model and the two Higgs doublet model, although it is not the case for experimental values of the parameters.

Original languageEnglish
Article number99
JournalJournal of High Energy Physics
Issue number2
Publication statusPublished - 2022 Feb


  • Higgs Physics
  • Solitons Monopoles and Instantons

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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