{
  "id": "2406.07606",
  "version": "v1",
  "published": "2024-06-11T18:00:00.000Z",
  "updated": "2024-06-11T18:00:00.000Z",
  "title": "String loops and gravitational positivity bounds: imprint of light particles at high energies",
  "authors": [
    "Simon Caron-Huot",
    "Junsei Tokuda"
  ],
  "comment": "27 pages + 4 appendices, 14 figures",
  "categories": [
    "hep-th",
    "hep-ph"
  ],
  "abstract": "We study loop corrections to positivity bounds on effective field theories in the context of $2\\to 2$ scattering in gravitational theories, in the presence of light particles. It has been observed that certain negative contributions at low energies are enhanced by inverse powers of a small mass $m$ and are nontrivial to cancel against other low-energy contributions. These originate from near the forward limit of diagrams involving graviton exchange. We observe that scattering in this kinematics domain remains infrared-sensitive even at high center-of-mass energy. By considering a string-inspired model in which high-energy loops can be calculated using unitarity and Regge behavior of tree amplitudes, we uncover a natural mechanism through which $1/m$-enhanced terms perfectly cancel between low and high energy contributions. This concretely explains possible positivity violations in the presence of gravity from the high-energy viewpoint.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-06-11T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "gravitational positivity bounds",
      "light particles",
      "string loops",
      "high energy contributions",
      "kinematics domain remains"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 27,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}