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Title: Measurement of the Ratio of Inclusive Cross Sections σ (p anti-p → Z + b-jet) / σ (p anti-p → Z + jet) at √s = 1.96-TeV

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/15011745· OSTI ID:15011745
 [1]
  1. Stony Brook Univ., NY (United States)

Using the data collected with the D0 detector at √s = 1.96 TeV with integrated luminosities of about 180 pb-1, we have measured the ratio of inclusive cross sections for p$$\bar{p}$$ → Z + b-jet to p$$\bar{p}$$ → Z + jet production. The inclusive Z + b-jet reaction is an important background to searches for the Higgs boson in associated ZH production at the Fermilab Tevatron collider and is sensitive to the b quark content of the proton. This thesis describes our measurement which is performed using the dimuon decay channel of the Z boson, i.e. Z → μ+μ-. The ratio in the dimuon channel is measured to be 1.86 ± 0.44(stat)$$+0.24\atop{-0.28}$$(syst)% for hadronic jets with transverse momenta pT > 20 GeV/c and pseudorapidities |η| < 2.5, consistent with next-to-leading order predictions of the standard model. This measurement is also combined with the result of the same ratio using the dielectron decay of the Z boson, and the combined measurement of the ratio of cross-sections yields 2.11 ± 0.41(stat)$$+0.22\atop{-0.25}$$(syst)%. In addition to our measurement, we also study optimization procedures for the search of Z(μ $$\bar{μ}$$)+b$$\bar{b}$$ signal at D0. We demonstrate that substantial improvements in the signal sensitivity can be obtained by choosing more optimal selection cuts tailored for this signal and by combining the attributes of the similar objects in the events like muons and jets.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC02-76CH03000
OSTI ID:
15011745
Report Number(s):
FERMILAB-THESIS-2005-03; TRN: US200612%%665
Country of Publication:
United States
Language:
English