{
  "abstract": "Extending our recent work (which focussed on the even-parity quadrupolar part of the waveform), we compute the even-parity octupolar contribution, $U_3$, to the gravitational waveform $W \\equiv \\frac{c^4 r}{4G} \\bar m^{i} \\bar m^{j } h_{i j}$ emitted during the scattering of two masses. We work within the Multipolar Post-Minkowskian (MPM) formalism, and use the 3.5 Post-Newtonian (PN) accurate radiation-reacted quasi-Keplerian representation of the hyperbolic motion. We explicitly evaluate the frequency-domain value $\\hat U_3(ω, θ,ϕ)$ of $U_3$ up to the 2-loop level, i.e. $ O(G^4)$ contributions to $h_{ij}(ω, θ,ϕ)$, corresponding to $O(G^3)$ contributions to $\\hat U_3(ω, θ,ϕ)$. As a crucial partial confirmation of our result, we find that the 1-loop truncation of our 3.5 PN frequency-domain MPM waveform agrees with corresponding existing Effective Field Theory (EFT) results when taking into account exactly the {\\it same} (2.5PN-level) difference in the definitions of the center-of-mass origins within the two formalisms that was deduced from our previous quadrupolar comparison.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.11835",
  "author_total": 3,
  "authors": [
    {
      "name": "Donato Bini"
    },
    {
      "name": "Thibault Damour"
    },
    {
      "name": "Andrea Geralico"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8s9nf7vx6qzvh.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.11835",
  "fulltext_url": null,
  "id": "8s9nf7vx6qzvh",
  "issns": [],
  "landing_url": "https://hal.science/hal-05761200v1",
  "language": "en",
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "hal",
      "0.phys"
    ],
    [
      "hal",
      "1.phys.grqc"
    ],
    [
      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
    ]
  ],
  "openalex": "W7212306584",
  "pdf_url": "https://arxiv.org/pdf/2609.11835",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-10",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8s9nf7vx6qzvh.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:39Z",
      "native_id": "hal-05761200",
      "source": "hal",
      "url": "https://hal.science/hal-05761200v1"
    },
    {
      "first_seen": "2026-10-30T12:20:26Z",
      "native_id": "2609.11835",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.11835"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Octupolar bremsstrahlung waveform up to the two-loop level and the third-and-a-half post-Newtonian accuracy",
  "title_text": "Octupolar bremsstrahlung waveform up to the two-loop level and the third-and-a-half post-Newtonian accuracy",
  "type": "preprint",
  "updated_at": "2026-10-30T12:20:26Z",
  "url": "https://research.draconitic.com/paper/8s9nf7vx6qzvh",
  "venue": "HAL",
  "versions": []
}