{
  "abstract": "A fundamental open question in hadron spectroscopy is whether the radial excitation ladder of heavy mesons terminates at a finite level once confinement is screened by light-quark pair creation. We address this question for the mixed-flavor mesons $D_s$, $B_s$, and $B_c$ by solving a screened Godfrey--Isgur Hamiltonian with the Gaussian expansion method. The screening length is fixed by threshold-dependent string breaking analysis, and is matched to the charmonium and bottomonium anchors. The calculated spectra saturate at $3.36$, $6.78$, and $8.19~{\\rm GeV}$ in $D_s$, $B_s$, and $B_c$ families, while the RMS radii grow by several fm and mass gaps fall below $10~{\\rm MeV}$. Mass-radius decoupling places the end of the safe radial ladder at $n_{\\mathrm{safe}}\\approx 4$--$6$ for $D_s$, $5$--$7$ for $B_s$, and $9$--$11$ for $B_c$, so the ladder terminates first in $D_s$, then in $B_s$, and last in $B_c$. Above the limiting-mass windows, at $3.49$, $6.86$, and $8.24~{\\rm GeV}$, states of the radial ladder cannot be discovered. This termination is directly testable with forthcoming high-statistics data from BESIII, Belle II, and LHCb.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.34734",
  "author_total": 2,
  "authors": [
    {
      "name": "Wen-Xuan Zhang"
    },
    {
      "name": "Wen-Nian Liu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dt22nrjg6bnze.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.34734",
  "fulltext_url": null,
  "id": "dt22nrjg6bnze",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.34734",
  "language": null,
  "licence": "CC-BY-SA-4.0",
  "licence_label": "CC BY-SA 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-sa/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|Quantum Chromodynamics and Particle Interactions"
    ]
  ],
  "openalex": "W7214759351",
  "pdf_url": "https://arxiv.org/pdf/2609.34734",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dt22nrjg6bnze.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:12Z",
      "native_id": "2609.34734",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.34734"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Termination of the Radial Ladder in Mixed-Flavor Heavy Mesons",
  "title_text": "Termination of the Radial Ladder in Mixed-Flavor Heavy Mesons",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:12Z",
  "url": "https://research.draconitic.com/paper/dt22nrjg6bnze",
  "venue": "arXiv",
  "versions": []
}