{
  "id": "1105.2484",
  "version": "v2",
  "published": "2011-05-12T14:25:05.000Z",
  "updated": "2011-08-15T15:39:16.000Z",
  "title": "A simple relation between the gamma N -> N(1535) helicity amplitudes",
  "authors": [
    "G. Ramalho",
    "K. Tsushima"
  ],
  "comment": "Version accepted for publication in Phys.Rev.D. 4 pages, 3 figures",
  "journal": "Phys.Rev.D84:051301,2011",
  "doi": "10.1103/PhysRevD.84.051301",
  "categories": [
    "hep-ph",
    "hep-ex",
    "hep-lat",
    "nucl-ex",
    "nucl-th"
  ],
  "abstract": "It is shown that the helicity amplitudes A_1/2 and S_1/2 in the gamma N -> N(1535) reaction, can be well related by S_1/2 = -\\frac{\\sqrt{1+\\tau}}{\\sqrt{2}} \\frac{M_S^2-M^2}{2 M_S Q} A_1/2 in the region Q^2 > 2 GeV^2, where M and M_S are the nucleon and N(1535) masses, q^2=-Q^2 the four-momentum transfer squared, and tau=\\sfrac{Q^2}{(M_S+M)^2}. The observed relation is tested by the experimental data and the MAID parametrization. A direct consequence of the relation is that the assumption,|A_1/2| >> |S_1/2|, is not valid for high Q^2. Instead, both amplitudes A_1/2 and S_1/2 have the same Q^2 dependence in the high Q^2 region, aside from that S_{1/2} has an extra factor,-\\sfrac{1}{\\sqrt{2}}\\sfrac{M_S-M}{2M_S}. The origin of this relation is interpreted in a perspective of a quark model.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2011-08-15T15:39:16.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "14.20.Gk",
      "13.40.Gp",
      "12.39.Ki"
    ],
    "keywords": [
      "helicity amplitudes",
      "simple relation",
      "quark model",
      "experimental data",
      "maid parametrization"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review D",
      "year": 2011,
      "month": "Sep",
      "volume": 84,
      "number": 5,
      "pages": "051301"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 899312,
      "adsabs": "2011PhRvD..84e1301R"
    }
  }
}