{
  "id": "hep-ex/9709006",
  "version": "v1",
  "published": "1997-09-06T11:42:14.000Z",
  "updated": "1997-09-06T11:42:14.000Z",
  "title": "Measurement of the W Boson Mass and Production and Decay Properties in e^+e^- Collisions at sqrt{s} = 172 GeV",
  "authors": [
    "The OPAL Collaboration",
    "K. Ackerstaff et al"
  ],
  "comment": "59 pages, LaTeX, uses a4p and pennames.sty, 17 eps figures included (plus one in colour) to be submitted to Zeit. Phys. C",
  "journal": "Eur.Phys.J.C1:395-424,1998",
  "doi": "10.1007/s100520050093",
  "categories": [
    "hep-ex"
  ],
  "abstract": "This paper describes the measurement of the W boson mass, M_W, and decay width, Gamma_W, from the direct reconstruction of the invariant mass of its decay products in W pair events collected at a mean centre-of-mass energy of sqrt{s} = 172.12 GeV with the OPAL detector at LEP. Measurements of the W pair production cross-section, the W decay branching fractions and properties of the W decay final states are also described. A total of 120 candidate W^+W^- events has been selected for an integrated luminosity of 10.36 pb^-1. The W^+W^- production cross-section is measured to be sigma_WW = 12.3 +/- 1.3(stat.) +/- 0.3(syst.) pb, consistent with the Standard Model expectation. The W^+W^- -> qq(bar) l nu and W^+W^- -> qq(bar)qq(bar) final states are used to obtain a direct measurement of Gamma_W = 1.30^{+0.62}_{-0.55}(stat.) +/- 0.18(syst.) GeV. Assuming the Standard Model relation between M_W and Gamma_W, the W boson mass is measured to be M_W = 80.32 +/- 0.30(stat.) +/- 0.09(syst.) GeV. The event properties of the fully-hadronic decays of W^+W^- events are compared to those of the semi-leptonic decays. At the current level of precision there is no evidence for effects of colour reconnection in the observables studied. Combining data recorded by OPAL at sqrt{s} ~ 161-172 GeV, the W boson branching fraction to hadrons is determined to be 69.8^{+3.0}_{-3.2}(stat.) +/- 0.7(syst.)%, consistent with the prediction of the Standard Model. The combined mass measurement from direct reconstruction and from the W^+W^- production cross-sections measured at sqrt{s} ~ 161 and sqrt{s} ~ 172 GeV is M_W = 80.35 +/- 0.24(stat.) +/- 0.07(syst.) GeV.",
  "revisions": [
    {
      "version": "v1",
      "updated": "1997-09-06T11:42:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "boson mass",
      "measurement",
      "decay properties",
      "direct reconstruction",
      "collisions"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "journal": "European Physical Journal C",
      "year": 1998,
      "volume": 1,
      "number": "3-4",
      "pages": 395
    },
    "note": {
      "typesetting": "LaTeX",
      "pages": 59,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 448093,
      "adsabs": "1998EPJC....1..395O"
    }
  }
}