{
  "id": "hep-ph/0002234",
  "version": "v6",
  "published": "2000-02-23T17:54:16.000Z",
  "updated": "2000-12-12T08:45:43.000Z",
  "title": "An updated analysis of eps'/eps in the standard model with hadronic matrix elements from the chiral quark model",
  "authors": [
    "Stefano Bertolini",
    "Jan O. Eeg",
    "Marco Fabbrichesi"
  ],
  "comment": "15 pages, 11 figures, RevTeX, discussion updated, refs added",
  "journal": "Phys.Rev. D63 (2001) 056009",
  "doi": "10.1103/PhysRevD.63.056009",
  "categories": [
    "hep-ph"
  ],
  "abstract": "We discuss the theoretical and experimental status of the CP violating ratio eps'/eps. We revise our 1997 standard-model estimate-based on hadronic matrix elements computed in the chiral quark model up to O(p^4) in the chiral expansion-by including an improved statistical analysis of the uncertainties and updated determination of the Cabibbo-Kobayashi-Maskawa elements and other short-distance parameters. Using normal distributions for the experimental input data we find Re eps'/eps = (2.2 \\pm 0.8) x 10^{-3}, whereas a flat scanning gives 0.9 x 10^{-3} < Re eps'/eps < 4.8 x 10^{-3}. Both results are in agreement with the current experimental data. The key element in our estimate is, as before, the fit of the Delta I=1/2 rule, which allows us to absorb most of the theoretical uncertainties in the determination of the model-dependent parameters in the hadronic matrix elements. Our semi-phenomenological approach leads to numerical stability against variations of the renormalization scale and scheme dependence of the short- and long-distance components. The same dynamical mechanism at work in the selection rule also explains the larger value obtained for \\ratio with respect to other estimates. A coherent picture of K -> pi pi decays is thus provided.",
  "revisions": [
    {
      "version": "v6",
      "updated": "2000-12-12T08:45:43.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hadronic matrix elements",
      "chiral quark model",
      "standard model",
      "updated analysis",
      "pi pi decays"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. D"
    },
    "note": {
      "typesetting": "RevTeX",
      "pages": 15,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 524265
    }
  }
}