{
  "id": "2209.03971",
  "version": "v1",
  "published": "2022-09-08T18:00:03.000Z",
  "updated": "2022-09-08T18:00:03.000Z",
  "title": "The LPM effect in sequential bremsstrahlung: incorporation of \"instantaneous'' interactions for QCD",
  "authors": [
    "Peter Arnold",
    "Tyler Gorda",
    "Shahin Iqbal"
  ],
  "comment": "33 pages, 17 figures",
  "categories": [
    "hep-ph",
    "nucl-th"
  ],
  "abstract": "The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. We continue study of the case when the coherence lengths (formation lengths) of two consecutive splitting processes overlap, avoiding soft-emission approximations. Previous work made a ``nearly-complete'' calculation of the effect of overlapping formation times on gluonic splittings such as $g \\to gg \\to ggg$ (with simplifying assumptions such as an infinite QCD medium and the large-$N_c$ limit). In this paper, we extend those previous rate calculations from nearly-complete to complete by including processes involving the exchange of longitudinally-polarized gluons. In the context of Lightcone Pertubation Theory, used earlier for the ``nearly-complete'' calculation, such exchanges are instantaneous in lightcone time and have their own diagrammatic representation.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-09-08T18:00:03.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "lpm effect",
      "sequential bremsstrahlung",
      "incorporation",
      "interactions",
      "lightcone pertubation theory"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 33,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}