{
  "annotation_id": "581ac013-11bf-43a8-b995-87e3e332b0dc",
  "date_created": "2026-03-02T18:01:25.017000Z",
  "date_modified": "2026-03-02T18:01:25.017000Z",
  "file_hash": "628c4dba871b47bb04a89b84259594e9e9d9c41d9dbc244452e3344e20cfa447",
  "private": false,
  "record": {
    "abstract": "We give an overview of track fitting using the Kalman filter method in the\nNOMAD detector at CERN, and emphasize how the wealth of by-product information\ncan be used to analyze track breakpoints (discontinuities in track parameters\ncaused by scattering, decay, etc.). After reviewing how this information has\nbeen previously exploited by others, we describe extensions which add power to\nbreakpoint detection and characterization. We show how complete fits to the\nentire track, with breakpoint parameters added, can be easily obtained from the\ninformation from unbroken fits. Tests inspired by the Fisher F-test can then be\nused to judge breakpoints. Signed quantities (such as change in momentum at the\nbreakpoint) can supplement unsigned quantities such as the various chisquares.\nWe illustrate the method with electrons from real data, and with Monte Carlo\nsimulations of pion decays.",
    "arxiv_id": "physics/9912034",
    "authors": [
      "Pierre Astier",
      "Alessandro Cardini",
      "Robert D. Cousins",
      "Antoine Letessier-Selvon",
      "Boris A. Popov",
      "Tatiana Vinogradova"
    ],
    "categories": [
      "physics.data-an"
    ],
    "doi": "10.1016/S0168-9002(00)00154-6",
    "journal_ref": "Nucl.Instrum.Meth. A450 (2000) 138-154",
    "title": "Kalman Filter Track Fits and Track Breakpoint Analysis",
    "url": "https://arxiv.org/abs/physics/9912034"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "5be148ae-3dfe-4a34-88bc-54e49dac662e",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}