{
  "abstract": "We review the harmonic superspace formalism for 4d $\\mathcal{N}=2$ theories and apply it to orbifolds of $\\mathcal N=4$ Super-Yang-Mills (SYM) theory. These theories have a remarkably similar description to $\\mathcal N=4$ SYM, but their planar supergraphs feature topological twist lines which generate phases when intersecting bifundamental hypermultiplet propagators. These cause twisted sector BPS correlators to depend on the coupling $g$. Twisted Coulomb-branch operators of length $L$ receive a leading perturbative contribution to their two-point function at order $\\mathcal{O}(g^{2L})$ from a supergraph involving a wrapped hypermultiplet circle. After performing the complete $D$-algebra, we show that the supergraph reduces to the universal conformal period $W_L=\\binom{2L}{L}ζ(2L-1)$. We extend this analysis to multiple nested hypermultiplet circles and show that they reproduce a series of higher-order terms in the exact localisation result. A subsequent evaluation of leading contributions to BPS three-point correlators again shows complete agreement with localisation results in extremal case and generates new perturbative data in the non-extremal case. The latter involves one untwisted BPS descendant, which contains physical hypermultiplet fields and can therefore connect directly to the twist-dependent hypermultiplet circle. This reduces the suppression in $g$, resulting in a contribution $4 g^{2(\\ell+1)} W_{\\ell+1}$ controlled by a bridge length $\\ell$ rather than by an external operator length $L\\geq\\ell$. These examples demonstrate the feasibility of harmonic superspace calculations in orbifold theories and point to various future applications in the context of non-BPS correlators, integrability and marginal deformations.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.28733",
  "author_total": 2,
  "authors": [
    {
      "name": "Dennis le Plat"
    },
    {
      "name": "Torben Skrzypek"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6sv0fxxes7r1y.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.28733",
  "fulltext_url": null,
  "id": "6sv0fxxes7r1y",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.28733",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3106|Black Holes and Theoretical Physics"
    ]
  ],
  "openalex": "W7223214864",
  "pdf_url": "https://arxiv.org/pdf/2610.28733",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-20",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6sv0fxxes7r1y.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:19Z",
      "native_id": "2610.28733",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.28733"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "Circling in on correlation functions in $\\mathcal{N}=2$ orbifold theories",
  "title_text": "Circling in on correlation functions in 𝒩=2 orbifold theories",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:16Z",
  "url": "https://research.draconitic.com/paper/6sv0fxxes7r1y",
  "venue": "arXiv",
  "versions": []
}