{
  "annotation_id": "c1170d1d-8989-4c81-84f5-ce646d108b33",
  "date_created": "2026-03-02T18:00:43.005000Z",
  "date_modified": "2026-03-02T18:00:43.005000Z",
  "file_hash": "ca11c6df7797db183123c5abf9d55ee4d90fff67b6485af235c1d6887b00c7de",
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  "record": {
    "abstract": "We have applied an optical method to the measurement of the 2S hyperfine\ninterval in atomic hydrogen. The interval has been measured by means of\ntwo-photon spectroscopy of the 1S-2S transition on a hydrogen atomic beam\nshielded from external magnetic fields. The measured value of the 2S hyperfine\ninterval is equal to 177 556 860(15) Hz and represents the most precise\nmeasurement of this interval to date. The theoretical evaluation of the\nspecific combination of 1S and 2S hyperfine intervals D_21 is in moderately\ngood agreement with the value for D_21 deduced from our measurement.",
    "arxiv_id": "physics/0305073",
    "authors": [
      "N. Kolachevsky",
      "M. Fischer",
      "S. G. Karshenboim",
      "T. W. Haensch"
    ],
    "categories": [
      "physics.atom-ph"
    ],
    "doi": "10.1103/PhysRevLett.92.033003",
    "journal_ref": "Phys. Rev. Lett. 92, 033003 (2004)",
    "title": "High-Precision Optical Measurement of the 2S Hyperfine Interval in   Atomic Hydrogen",
    "url": "https://arxiv.org/abs/physics/0305073"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "2155aece-5a74-4e0b-b692-6d8c13d3bad1",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}