{
  "id": "2002.12821",
  "version": "v1",
  "published": "2020-02-28T15:49:15.000Z",
  "updated": "2020-02-28T15:49:15.000Z",
  "title": "Triangle singularity in $B^-\\to K^-X(3872);X\\to π^0π^+π^-$ and the X(3872) mass",
  "authors": [
    "Raquel Molina",
    "Eulogio Oset"
  ],
  "comment": "10 pages,10 figures",
  "categories": [
    "hep-ph"
  ],
  "abstract": "We evaluate the contribution to the $X(3872)$ width from a triangle mechanism in which the $X$ decays into $D^{*0}\\bar{D}^0 -cc$, then the $D^{*0} (\\bar{D}^{*0})$ decays into $D^0 \\pi^0$ ($\\bar{D}^0 \\pi^0$) and the $D^0 \\bar{D}^0$ fuse to produce $\\pi^+ \\pi^-$. This mechanism produces a triangle singularity visible at a precise value of the $\\pi^+ \\pi^-$ invariant mass, very sensitive to the $X$ mass. The shape of the $M_\\mathrm{Inv}(\\pi^+ \\pi^-)$ distribution is also very sensitive to this mass. We evaluate the branching ratios for a reaction where this effect can be seen in the $B^- \\to K^- \\pi^0 \\pi^+ \\pi^-$ reaction and show that the determination of the peak in the invariant mass distribution of the $\\pi^+ \\pi^-$, which can be done with high precision, is all that is needed to determine the $X$ mass. Given the present uncertainties in the $X$ mass, which do not allow to know whether the $D^{*0} \\bar{D}^0$ state is bound or not, measurements like the one suggested here should be most welcome to clarify this issue.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-02-28T15:49:15.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "invariant mass distribution",
      "mechanism produces",
      "high precision",
      "triangle mechanism",
      "precise value"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}