A Measurement of the Ratio of Inclusive Cross Sections pp->Z+b-jet/pp->Z+jet at sqrt(s) = 1.96-TeV

Abstract

Using the data collected with the DZero detector at sqrt(s)=1.96-TeV, for integrated luminosities of about 180 pb^{-1}, we have measured the ratio of inclusive cross sections for p+pbar->Z+bjet to p+pbar->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. Our measurement is the first of its kind, and relies on the Z->e^+e^- and Z->mu^+mu^- modes. The combined measurement of the ratio yields 0.023 +/- 0.005 for hadronic jets with transverse momenta p_T>20 GeV/c and pseudorapidities |eta|<2.5, consistent with next-to-leading order predictions of the standard model.

Figures (2)

• Figure 1: The $p_{T}$ distribution of taggable jets in dielectron and dimuon channels compared to $Z+$jet alpgen with pythia showering and full detector simulation (open histogram), and background (multijet for $ee$ channel and $b\bar{b}$ background for $\mu\mu$ channel) derived from data. The error bars on the data points are statistical. The prediction is normalized to the data, as described in the text.
• Figure 2: (a) The $p_T$ spectrum for $b$-tagged jets. (b) Distribution in decay-length significance of secondary vertices in the transverse plane, without the requirement on decay-length significance. All error bars are statistical.