{
  "id": "1505.05282",
  "version": "v1",
  "published": "2015-05-20T08:37:06.000Z",
  "updated": "2015-05-20T08:37:06.000Z",
  "title": "Testing the consistency of the $ωπ$ transition form factor with unitarity and analyticity",
  "authors": [
    "I. Caprini"
  ],
  "categories": [
    "hep-ph"
  ],
  "abstract": "We perform a dispersive analysis of the $\\omega\\pi$ electromagnetic transition form factor, using as input the discontinuity provided by unitarity below the $\\omega\\pi$ threshold and including for the first time experimental data on the modulus measured from $e^+e^-\\to\\omega\\pi^0$ at higher energies. The input leads to stringent parameterization-free constraints on the modulus of the form factor below the $\\omega\\pi$ threshold, which are in disagreement with some experimental values measured from $\\omega\\to \\pi^0\\gamma^*$ decay. We discuss the dependence on the input parameters in the unitarity relation, using for illustration an $N/D$ formalism for the P partial wave of the scattering process $\\omega\\pi \\to \\pi\\pi$, improved by a simple prescription which simulates the rescattering in the crossed channels. Our results confirm the existence of a conflict between experimental data and theoretical calculations of the $\\omega\\pi$ form factor in the region around 0.6 GeV and bring further arguments in support of renewed experimental efforts to measure more precisely the $\\omega\\to\\pi^0\\gamma^*$ decay.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-05-20T08:37:06.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "13.40.Gp",
      "11.55.Fv",
      "13.25.Jx"
    ],
    "keywords": [
      "analyticity",
      "consistency",
      "electromagnetic transition form factor",
      "first time experimental data",
      "stringent parameterization-free constraints"
    ],
    "publication": {
      "doi": "10.1103/PhysRevD.92.014014"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1371860
    }
  }
}