{
  "abstract": "We study the future prospects for precision measurements of purely leptonic charged-current kaon and pion decays. Together with the ratio of leptonic widths $R_K^ν=Γ(K\\to eν)/Γ(K\\toμν)$, we consider the single ratios $R_{Kπ}^{\\ell=μ,e} = Γ(K \\to \\ellν) / Γ(π\\to \\ellν)$, for which many experimental uncertainties cancel, as well as the double ratio $R_{Kπ}^e / R_{Kπ}^μ$, which provides a particularly sensitive probe of new physics. This study is timely in light of two converging developments. On the experimental side, a new conceptual design for a dedicated setup based on a slow-extracted proton beam and a multi-year data-taking program, is expected to achieve a precision at the few $10^{-4}$ level. On the theory side, recent lattice-QCD calculations have reached a comparable level of accuracy. Finally, we assess the impact of these next-generation measurements on searches for physics beyond the Standard Model and show that they can provide constraints that are either competitive with or complementary to existing bounds.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.05231",
  "author_total": 5,
  "authors": [
    {
      "name": "Lukas Allwicher"
    },
    {
      "name": "Stefan Alexandru Ghinescu"
    },
    {
      "name": "Federico Mescia"
    },
    {
      "name": "Tommaso Spadaro"
    },
    {
      "name": "Lucine Tabatt"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fjtn9tyzth45m.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.05231",
  "fulltext_url": null,
  "id": "fjtn9tyzth45m",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.05231",
  "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-ex"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|Particle physics theoretical and experimental studies"
    ]
  ],
  "openalex": "W7211886397",
  "pdf_url": "https://arxiv.org/pdf/2609.05231",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fjtn9tyzth45m.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2609.05231",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.05231"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    }
  ],
  "title": "New measurements in leptonic kaon and pion decays: experimental and theoretical perspectives",
  "title_text": "New measurements in leptonic kaon and pion decays: experimental and theoretical perspectives",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/fjtn9tyzth45m",
  "venue": "arXiv",
  "versions": []
}