{
  "id": "hep-ex/0604031",
  "version": "v1",
  "published": "2006-04-14T19:11:42.000Z",
  "updated": "2006-04-14T19:11:42.000Z",
  "title": "Observation of $Υ(4S) decays to $π^+pi^-Υ(1S)$ and $π^+pi^-Υ(2S)",
  "authors": [
    "The BABAR Collaboration",
    "B. Aubert"
  ],
  "comment": "7 pages,, 3 figures,submitted to Physical Review Letters",
  "journal": "Phys.Rev.Lett.96:232001,2006",
  "doi": "10.1103/PhysRevLett.96.232001",
  "categories": [
    "hep-ex"
  ],
  "abstract": "We present the first measurement of $\\Upsilon(4S)$ decays to $\\pi^+pi^-\\Upsilon(1S)$ and $\\pi^+pi^-\\Upsilon(2S)$ based on a sample of 230$\\times10^6$ $\\Upsilon(4S)$ mesons collected with the BABAR detector. We measure the product branching fractions ${\\cal B}(\\Upsilon(4S)\\to \\pi^+pi^-\\Upsilon(1S))\\times{\\cal B}(\\Upsilon(1S)\\to\\mu^+\\mu^-)=(2.23\\pm0.25_{stat} \\pm0.27_{sys})\\times 10^{-6}$ and ${\\cal B}(\\Upsilon(4S)\\to \\pi^+pi^-\\Upsilon(2S))\\times{\\cal B}(\\Upsilon(2S)\\to\\mu^+\\mu^-)=(1.69\\pm0.26_{stat}\\pm0.20_{sys})\\times 10^{-6}$, from which we derive the partial widths $\\Gamma(\\Upsilon(4S)\\to \\pi^+pi^-\\Upsilon(1S))=(1.8\\pm0.4)$~keV and $\\Gamma(\\Upsilon(4S)\\to \\pi^+pi^-\\Upsilon(2S))=(2.7\\pm0.8)$~keV.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2006-04-14T19:11:42.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "13.25.Gv",
      "14.40.Gx"
    ],
    "keywords": [
      "observation",
      "first measurement",
      "partial widths",
      "product branching fractions"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. Lett."
    },
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 714448
    }
  }
}