{
  "id": "1307.6653",
  "version": "v2",
  "published": "2013-07-25T07:59:42.000Z",
  "updated": "2013-12-26T18:00:41.000Z",
  "title": "Effective theory approach to new physics in $b \\to u$ and $b \\to c$ leptonic and semileptonic decays",
  "authors": [
    "Rupak Dutta",
    "Anupama Bhol",
    "Anjan K Giri"
  ],
  "comment": "32 pages, 8 figures, published version",
  "journal": "Phys. Rev. D 88, 114023 (2013)",
  "doi": "10.1103/PhysRevD.88.114023",
  "categories": [
    "hep-ph"
  ],
  "abstract": "Recent measurements of exclusive $B^{-} \\to \\tau^{-}\\,\\nu$ and $B^0 \\to \\pi^{+}\\,l^{-}\\,\\bar{\\nu}_l$ decays via the $b \\to u\\,l\\,\\nu$ transition process differ from the standard model expectation and, if they persist in future $B$ experiments, will be a definite hint of the physics beyond the standard model. Similar hints of new physics have been observed in $b \\to c$ semileptonic transition processes as well. BABAR measures the ratio of branching fractions of $B \\to (D,\\,D^{\\ast})\\,\\tau\\,\\nu$ to the corresponding $B \\to (D,\\,D^{\\ast})\\,l\\nu$, where $l$ represents either an electron or a muon, and finds $3.4\\sigma$ discrepancy with the standard model expectation. In this context, we consider a most general effective Lagrangian for the $b \\to u\\,l\\,\\nu$ and $b \\to c\\,l\\,\\nu$ transition processes in the presence of new physics and perform a combined analysis of all the $b \\to u$ and $b \\to c$ semi-(leptonic) data to explore various new physics operators and their couplings. We consider various new physics scenarios and give predictions for the $B_c \\to \\tau\\nu$ and $B \\to \\pi\\tau\\nu$ decay branching fractions. We also study the effect of these new physics parameters on the ratio of the branching ratios of $B \\to \\pi\\tau\\nu$ to the corresponding $B \\to \\pi\\,l\\,\\nu$ decays.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2013-12-26T18:00:41.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "14.40.Nd",
      "13.20.He",
      "13.20.-v"
    ],
    "keywords": [
      "effective theory approach",
      "semileptonic decays",
      "standard model expectation",
      "transition process differ",
      "semileptonic transition processes"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review D",
      "year": 2013,
      "month": "Dec",
      "volume": 88,
      "number": 11,
      "pages": 114023
    },
    "note": {
      "typesetting": "TeX",
      "pages": 32,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1244532,
      "adsabs": "2013PhRvD..88k4023D"
    }
  }
}