{
  "id": "hep-ex/0107071",
  "version": "v1",
  "published": "2001-07-25T14:33:40.000Z",
  "updated": "2001-07-25T14:33:40.000Z",
  "title": "Observation of Diffractive $J/ψ$ Production at the Fermilab Tevatron",
  "authors": [
    "T. Affolder"
  ],
  "comment": "9 pages, 4 figures, using RevTeX. Submitted to Physical Review Letters",
  "journal": "Phys.Rev.Lett.87:241802,2001",
  "doi": "10.1103/PhysRevLett.87.241802",
  "categories": [
    "hep-ex"
  ],
  "abstract": "We report the first observation of diffractive $J/\\psi(\\to \\mu^+\\mu^-)$ production in $\\bar pp$ collisions at $\\sqrt{s}$=1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum $p_T^{\\mu}>2$ GeV/$c$ within the pseudorapidity region $|\\eta|<$1.0, the ratio of diffractive to total $J/\\psi$ production rates is found to be $R_{J/\\psi}= [1.45\\pm 0.25]%$. The ratio $R_{J/\\psi}(x)$ is presented as a function of $x$-Bjorken. By combining it with our previously measured corresponding ratio $R_{jj}(x)$ for diffractive dijet production, we extract a value of $0.59\\pm 0.15$ for the gluon fraction of the diffractive structure function of the proton.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2001-07-25T14:33:40.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "fermilab tevatron",
      "rapidity gap signature",
      "first observation",
      "pseudorapidity region",
      "production rates"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. Lett."
    },
    "note": {
      "typesetting": "RevTeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 560628
    }
  }
}