{
  "id": "1108.2036",
  "version": "v2",
  "published": "2011-08-09T20:01:31.000Z",
  "updated": "2012-03-19T23:03:37.000Z",
  "title": "Next-to-Next-to-Leading-Order Charm-Quark Contribution to the CP Violation Parameter epsilon_K and Delta M_K",
  "authors": [
    "Joachim Brod",
    "Martin Gorbahn"
  ],
  "comment": "5 pages, 2 figures; typos corrected, references added, extended discussion of results, updated numerics, version as published in PRL",
  "journal": "Phys.Rev.Lett.108:121801,2012",
  "doi": "10.1103/PhysRevLett.108.121801",
  "categories": [
    "hep-ph"
  ],
  "abstract": "The observables epsilon_K and Delta M_K play a prominent role in particle physics due to their sensitivity to new physics at short distances. To take advantage of this potential, a firm theoretical prediction of the standard-model background is essential. The charm-quark contribution is a major source of theoretical uncertainty. We address this issue by performing a next-to-next-to-leading-order (NNLO) QCD analysis of the charm-quark contribution eta_cc to the effective |Delta S|=2 Hamiltonian in the standard model. We find a large positive shift of 36%, leading to eta_cc = 1.87(76). This result might cast doubt on the validity of the perturbative expansion; we mention possible solutions. Finally, we give an updated value of the standard-model prediction for |epsilon_K| = 1.81(28) x 10^-3 and Delta M_K(SD) = 3.1(1.2) x 10^-15 GeV.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2012-03-19T23:03:37.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "12.38.Bx",
      "12.15.Hh",
      "11.30.Er",
      "13.25.Es"
    ],
    "keywords": [
      "cp violation parameter",
      "next-to-next-to-leading-order charm-quark contribution",
      "standard-model prediction",
      "short distances",
      "firm theoretical prediction"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review Letters",
      "year": 2012,
      "month": "Mar",
      "volume": 108,
      "number": 12,
      "pages": 121801
    },
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 922836,
      "adsabs": "2012PhRvL.108l1801B"
    }
  }
}