Search for a Light Higgs boson in the channel WH→ eνe b$$\bar{b}$$ in p$$\bar{p}$$-collision with $$\sqrt{s}$$ = 1.96 TeV in the D0 detector of the Tevatron (in German)
- Johannes Gutenberg Univ., Mainz (Germany)
Although the standard model of particle physics has been very successfull in describing nature it needs to be extended by the Higgs mechanism to explain the particle masses observed in experiments. This mechanism introduces a new elementary particle called the Higgs boson. Current research at particle accelerators focuses on the search for the Higgs boson as a major goal. This analysis uses the data recorded with the D0-detector of the Tevatron at the Fermi National Accelerator Laboratory (FNAL). The Tevatron collides protons and antiprotons at a center of mass energy of √s=1.96 TeV. The primary goal of the analysis was the search for a light Higgs boson in the WH channel. For this the process pp→ WH → ev bb was used. Furthermore a measurement of the Wbb production cross section has been performed. For the measurements a total intagrated luminosity of L=255pb-1 was available. For the selection of the desired processes events with electrons, missing transverse momentum and at least two jets have been used. At least two of the jets were required to be identified as b-jets. To obtain an efficient event selection many event properties had to be calculated and methods to cut on them needed to be optimized. Based on the selected events the Wbb production cross section has been calculated. After includinng the branching ratio BR(W→ev)=0.108 the result is σ(Wbb)=21.8 pb (+15.5; -20.0 pb(sys+stat)) for events where the b-quarks satisfy p_T>8 GeV und |η|<3. Since the significance of the signal is only about 1.2σ the data has also been used to calculate an upper limit on the production cross section. For a confidence level of 95% a value of σ95(Wbb)=60.9 pb has been obtained. The same basic event selection has been used to obtain an upper limit for the WH production cross section. For the statistical analysis of these events the method of Cousins and Feldman was used. This method was extended to include background uncertainties as proposed by Conrad et al. Finally for a standard model Higgs boson of 115 GeV mass an upper limit for the production cross section of σ95 (WH)=12.2 pb has been obatined at a confidence level of 95%. Although this limit is about two orders of magnitude above the prediction of the standard model this type of analysis will improve sufficiently as more data becomes available in the next few years.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 948153
- Report Number(s):
- FERMILAB-THESIS-2005-95; TRN: US0901547
- Country of Publication:
- United States
- Language:
- German
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