Book Description
The inclusive production of $b$-jets with a $Z$ boson is an important background to searches for the Higgs boson in associated $ZH \rightarrow llb\bar{b}$ production at the Fermilab Tevatroncollider. This thesis describes the most precise measurement to date of the ratio of inclusive cross sections $\sigma(p\bar{p} \rightarrow Z+b$-jet$)/\sigma(p\bar{p} \rightarrow Z+$jet$)$ when a $Z$ boson decays into two electrons or muons. The measurement uses a data sample from $p\bar{p}$ collisions at the center of mass energy $\sqrt{s}=1.96$ TeV corresponding to an integrated luminosity of 4.2 fb$^{-1}$ collected by the D0 detector. The measured ratio $\sigma(Z+b$-jet$)/\sigma(Z+$jet$)$ is $0.0187\pm0.0021(stat.) \pm0.0015(syst)$ for jets with transverse momentum $p_T$~$>$~20 GeV and pseudorapidity $\eta\leq$2.5. The measurement is compared with the next-to-leading order theoretical predictions from MCFM and is found to be consistent within uncertainties.
