{
  "abstract": "It is well known that a strictly massless spin-$3/2$ particle can interact consistently only within supergravity. Recently, positivity arguments have shown that an effective field theory of a massive Majorana spin-$3/2$ particle admits an arbitrarily small mass only if a graviton is present and the four-fermion contact interactions are tuned to the values dictated by $\\mathcal{N}=1$ supergravity. In this work, we investigate how this limit is approached at finite mass. Assuming that the graviton $t$-channel pole can be discarded, we derive non-forward, tree-level dispersive bounds on massive spin-3/2 contact operators and determine the region of effective couplings consistent with unitarity and analyticity. For sufficiently small $m$, we find that the allowed parameter space forms a bounded, Planck-suppressed neighbourhood of the supergravity point, defined by the supergravity values of the four-fermion couplings. The supergravity point lies on the boundary of this region. In the regime $m \\ll M_{\\rm Pl}$, the volume of the allowed region scales parametrically as \\[ \\mathrm{Vol} \\sim \\frac{m^{6}}{M_{\\rm Pl}^{6}} \\, , \\] and shrinks to zero as $m \\to 0$, smoothly reproducing the massless-limit results. The allowed region becomes unbounded when mass approaches the Planck scale. We further analyze the effect of including additional light scalar and pseudo-scalar degrees of freedom, motivated by the Polonyi model, and find that their couplings are also bounded in a way similar to the contact couplings and that it doesn't enlarge the allowed contact coupling space.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2605.11072",
  "author_total": 3,
  "authors": [
    {
      "name": "Jay Desai"
    },
    {
      "name": "Diptimoy Ghosh"
    },
    {
      "name": "Saurabh Pant"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cfrxgxjky1h3r.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.11072",
  "fulltext_url": null,
  "id": "cfrxgxjky1h3r",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.11072",
  "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"
    ],
    [
      "arxiv",
      "hep-th"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2605.11072",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/cfrxgxjky1h3r.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2605.11072",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.11072"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Positivity in Massive Spin-3/2 EFTs and the Planck-Suppressed Neighbourhood of Supergravity",
  "title_text": "Positivity in Massive Spin-3/2 EFTs and the Planck-Suppressed Neighbourhood of Supergravity",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/cfrxgxjky1h3r",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1007/jhep09(2026)265",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}