{
  "abstract": "We study phase structures, meson mass spectra, and sound velocities at finite temperature and density in QCD with isospin chemical potential ($μ_I$). We employ the quark-meson model with $N_f=2+1$, incorporating the Kobayashi-Maskawa-'t Hooft type coupling to capture dynamical effects of the $U(1)_A$ axial anomaly. Within the mean-field approximation at quark one-loop, we analyze the onset of pion condensation, which manifests as a second-order phase transition at low temperatures and may exhibit a first-order behavior at higher temperatures within this approximation. We examine the corresponding mass spectra of scalar and pseudoscalar singlet-octet mesons, in which the $π_+$ mass is exactly massless in the superfluid phase due to its Nambu-Goldstone boson nature. The neutral pion mass is, meanwhile, found to exhibit a strictly linear growth with $μ_I$ in the pion condensed phase. We also investigate the isothermal squared sound velocity and identify characteristic structures associated with the phase transitions. Furthermore, we highlight how enhanced $U(1)_A$ anomaly effects facilitate the pion condensate to generate a less-pronounced sound velocity peak in cold medium. Our findings are expected to provide future lattice simulations with useful information on meson mass spectra from symmetry aspects.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.03385",
  "author_total": 3,
  "authors": [
    {
      "name": "Yu-Han Gao"
    },
    {
      "name": "Xu-Guang Huang"
    },
    {
      "name": "Daiki Suenaga"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cgr2ym6dz2w0h.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.03385",
  "fulltext_url": null,
  "id": "cgr2ym6dz2w0h",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.03385",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|High-Energy Particle Collisions Research"
    ]
  ],
  "openalex": "W7208719370",
  "pdf_url": "https://arxiv.org/pdf/2609.03385",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-03",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/cgr2ym6dz2w0h.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:31Z",
      "native_id": "2609.03385",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.03385"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Meson mass spectrum in isospin QCD medium from the $N_f=2+1$ quark-meson model",
  "title_text": "Meson mass spectrum in isospin QCD medium from the N_f=2+1 quark-meson model",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:31Z",
  "url": "https://research.draconitic.com/paper/cgr2ym6dz2w0h",
  "venue": "arXiv",
  "versions": []
}