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Persistent URL http://purl.org/net/epubs/work/29678
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Record Id 29678
Title A Determination of the W Boson Mass near the W-pair Production Threshold
Abstract In 1996 the LEP Collider operated for the first time at collision energies above the W-pair production threshold. Electron-positron collisions were produced at centre of mass energies of 161 and 172 GeV. An integrated luminosity of approximately 10pb(-1) was collected by the DELPHI experiment at each of these energies. These data are used to measure the cross-section for the doubly resonant W(+)W(-) production. At sqrt(s) of 161.31+/-0.06 GeV we obtain: sigma(W(+)W(-))=3.82 (+1.06)(-0.93)(stat) +/- 0.25(syst) pb. At sqrt(s) of 172.30+/-0.06 GeV we obtain: sigma(W(+)W(-))=12.20 (+1.66)(-1.54)(stat) +/- 0.50(syst) pb. Results on the W boson branching ratios, the CKM matrix element mod(V(cs)), and an indirect determination of the W boson width are also provided. Near the W-pair production threshold, the Standard Model W(+)W(-) cross-section is sensitive to the W boson mass. We interpret the measured cross-sections, within the Standard Model, as a measurement of M(W). The W boson mass is also obtained from the method of invariant mass direct reconstruction in the W(+)W(-)-->1nu(bar)(1)qq(bar)' and W(+)W(-)-->qq(bar)'q(bar)q' final states. This method is applied to the data collected at 172 GeV. Combining the W boson mass measurements made by the direct reconstruction method and the threshold cross-section interpretation, we obtain the value: M(W)=80.14 +/- 0.31(stat) +/- 0.07(syst) +/- 0.02(int) +/- 0.03(LEP) GeV/c(2).
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Language English (EN)
Type Details URI(s) Local file(s) Year
Thesis RAL Theses RAL-TH-1998-008. 1998. 1998