{
  "id": "0710.2830",
  "version": "v1",
  "published": "2007-10-15T14:38:57.000Z",
  "updated": "2007-10-15T14:38:57.000Z",
  "title": "Precision extraction of a_nn from pi- d --> n n gamma using chiral perturbation theory",
  "authors": [
    "A. Gardestig",
    "D. R. Phillips"
  ],
  "comment": "Invited talk at MENU2007, 10 pages, 3 figures, uses conference.cls and MENU07macros.tex (provided)",
  "journal": "ECONF C070910:139,2007",
  "categories": [
    "nucl-th",
    "hep-ph"
  ],
  "abstract": "The neutron-neutron scattering length a_nn provides a sensitive probe of charge-symmetry breaking in the strong interaction. Here we summarize our recent efforts to use chiral perturbation theory in order to systematically relate a_nn to the shape of the neutron spectrum in the reaction pi- d --> n n gamma. In particular we show how the chiral symmetry of QCD relates this process to low-energy electroweak reactions such as p p --> d e+ nu_e. This allows us to reduce the uncertainty in the extracted a_nn (mainly due to short-distance physics in the two-nucleon system) by a factor of more than three, to <0.05 fm. We also report first results on the impact that two-nucleon mechanisms of chiral order P^4 have on the pi- d --> n n gamma neutron spectrum.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2007-10-15T14:38:57.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "chiral perturbation theory",
      "precision extraction",
      "gamma neutron spectrum",
      "low-energy electroweak reactions",
      "chiral symmetry"
    ],
    "tags": [
      "conference paper",
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 764200,
      "adsabs": "2007arXiv0710.2830G"
    }
  }
}