{
  "abstract": "Gravitational-wave observations of compact binaries offer a direct way to test whether gravity admits polarizations beyond the two tensor modes of general relativity. We perform a forecast to assess how well future multi-messenger events will constrain the presence of scalar polarizations in gravitational waves. Performing binary neutron star injections, we forecast next-generation constraints on three modified gravity parameters in the PPE formalism: $α$ (tensor amplitude), $α_B$ (scalar amplitude) and $β$ (tensor and scalar phase). Cosmic Explorer (CE) and Einstein Telescope (ET) each tighten every parameter by 1--2 orders of magnitude over an O5 LIGO-Virgo network, with ET's triangular geometry giving a persistent $\\approx2\\times$ improvement over 2$\\times$CE on the scalar-mode amplitude $α_B$ in both a GW170817-like and a second, representative BNS. We show that, if the sky position and luminosity distance are known from EM observations, adding an EM-based prior on the orbital inclination $ι$ narrows the $α_B$ constraint by $\\approx56\\times$ relative to an isotropic inclination prior, for a GW170817-like event. We also assess how EM inclination priors as well as assumptions on the neutron star equation of state may affect the inference on the scalar amplitude $α_B$. Overall, these results indicate that detector geometry and the availability of well-placed EM external information are both important levers --- alongside raw network sensitivity --- for next decade scalar-polarization tests.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.38956",
  "author_total": 2,
  "authors": [
    {
      "name": "Sk Md Adil Imam"
    },
    {
      "name": "Macarena Lagos"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/avrfcxv5fkkdp.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.38956",
  "fulltext_url": null,
  "id": "avrfcxv5fkkdp",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.38956",
  "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",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "astro-ph.IM"
    ],
    [
      "arxiv",
      "gr-qc"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.38956",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/avrfcxv5fkkdp.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:23Z",
      "native_id": "2610.38956",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.38956"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Probing Scalar Polarization with Next-Generation Gravitational-Wave Detectors: The Roles of Detector Geometry and Source Inclination",
  "title_text": "Probing Scalar Polarization with Next-Generation Gravitational-Wave Detectors: The Roles of Detector Geometry and Source Inclination",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:45Z",
  "url": "https://research.draconitic.com/paper/avrfcxv5fkkdp",
  "venue": "arXiv",
  "versions": []
}