{
  "annotation_id": "14217bf2-6b67-4b82-ab42-d59023e5e667",
  "date_created": "2026-03-02T18:00:18.957000Z",
  "date_modified": "2026-03-02T18:00:18.957000Z",
  "file_hash": "8e7a5c4fdcab5d50a375c0af99b6c4c10fd3b08b6423f0df5010be01ee65a688",
  "private": false,
  "record": {
    "abstract": "We study the dynamics of charged pions in the nuclear medium via the ratio of\ndifferential $\\pi^-$- and $\\pi^+$-spectra in a coupled-channel BUU (CBUU)\napproach. The relative energy shift of the charged pions is found to correlate\nwith the pion freeze-out time in nucleus-nucleus collisions as well as with the\nimpact parameter of the heavy-ion reaction. Furthermore, the long-range Coulomb\nforce provides a \u0027clock\u0027 for the expansion of the hot nuclear system. Detailed\ncomparisons with experimental data for $Au + Au$ at 1 GeV/A and $Ni + Ni$ at\n2.0 GeV/A are presented.",
    "arxiv_id": "nucl-th/9701057",
    "authors": [
      "S. Teis",
      "W. Cassing",
      "M. Effenberger",
      "A. Hombach",
      "U. Mosel",
      "Gy. Wolf"
    ],
    "categories": [
      "nucl-th"
    ],
    "doi": "10.1007/s002180050405",
    "journal_ref": "Z.Phys. A359 (1997) 297-304",
    "title": "Probing nuclear expansion dynamics with $\\pi^-/\\pi^+$-spectra",
    "url": "https://arxiv.org/abs/nucl-th/9701057"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "fd78d2ff-2661-47c9-a059-822ad3217992",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}