{
  "annotation_id": "cde565ac-d53a-4165-b461-daac65c19da5",
  "date_created": "2026-03-02T18:00:31.967000Z",
  "date_modified": "2026-03-02T18:00:31.967000Z",
  "file_hash": "49c3e629aade10cc2678fd2db926d386f6b90a8fd242b4efe8b6970ddf782725",
  "private": false,
  "record": {
    "abstract": "The quenching processes of the thermalized ortho-positronium(o-Ps) on an\noxygen molecule have been studied by the positron annihilation age-momentum\ncorrelation techinique(AMOC). The Doppler broadening spectrum of the 511 keV\ngamma-rays from the 2gamma annihilation of o-Ps in O_2 has been measured as a\nfunction of the o-Ps age. The rate of the quenching, consisting of the pickoff\nand the spin-conversion, is estimated from the positron lifetime spectrum. The\nratio of the pickoff quenching rate to the spin-conversion rate is deduced from\nthe Doppler broadening of the 511 keV gamma-rays from the annihilation of the\no-Ps. The pickoff parameter ^1Z_eff, the effective number of the electrons per\nmolecule which contribute to the pickoff quenching, for O_2 is determined to be\n0.6 +- 0.4. The cross-section for the elastic spin-conversion quenching is\ndetermined to be (1.16 +- 0.01) * 10^{-19} cm^2.",
    "arxiv_id": "physics/0011054",
    "authors": [
      "N. Shinohara",
      "N. Suzuki",
      "T. Chang",
      "T. Hyodo"
    ],
    "categories": [
      "physics.atom-ph",
      "physics.chem-ph"
    ],
    "doi": "10.1103/PhysRevA.64.042702",
    "title": "Pickoff and spin-conversion quenchings of ortho-positronium in oxygen",
    "url": "https://arxiv.org/abs/physics/0011054"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "cee1faf9-4223-42dd-a818-78a7c723c987",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}