Measurement of the W+bb b-jet Cross-Section Using 695 pb^-1

M. Soderberg, D. Gerdes (Michigan)

C. Neu (Penn)

We present a measurement of the b-jet cross-section for W+bb events in the tagged lepton+jets data sample. The cross-section is defined to proportional to the number of b-jets in W+bb events containing one or two hadron jets with E_T> 20.0 GeV and |&eta|< 2.0, and also posessing W-decay products with p_T(l^±)> 20.0 GeV, |&eta(l^±)|< 1.1, and p_T(&nu)> 25.0 GeV. The method relies on fits of the invariant mass of SECVTX tagged jets to isolate the contribution of b-decays.

In 695 pb^-1 of Run II data, we measure: Sigma = 0.90 ± 0.20 (stat.) ± 0.30 (syst.) GeV

Public Note

• CDF Note 8410

Blessed Plots

Left: Plot of the SECVTX mass templates for different flavors (pdf,gif). Right: Fit of the flavor content of the tagged jets in the data sample (pdf,gif).

Summary of the number of tagged b-jets from background (non-W+bb) processes (pdf,png). Uncertainties shown are those due to Monte Carlo statistics and theoretical cross-sections.

Systematic uncertainties for this analysis (pdf,png).

SECVTX of tagged jets in the data, after removing the expected charm and light-flavor contribution, overlayed with expected tagged b-jet shape from calculated background/signal composition (pdf,gif).

Left: E_T distribution of tagged jets in data, overlayed with distributions from different flavors (normalized to the fractions from the SECVTX mass fit) (pdf,gif). Right: &eta distribution of tagged jets in data, overlayed with distributions from different flavors (normalized to the fractions from the SECVTX mass fit) (pdf,gif).

Left: N-Tracks distribution of tagged jets in data, overlayed with distributions from different flavors (normalized to the fractions from the SECVTX mass fit) (pdf,gif). Right: N-Vertex-Tracks distribution of tagged jets in data, overlayed with distributions from different flavors (normalized to the fractions from the SECVTX mass fit) (pdf,gif).

Left: Pseudo C-Tau distribution of tagged jets in data, overlayed with distributions from different flavors (normalized to the fractions from the SECVTX mass fit) (pdf,gif). Right: L_xy distribution of tagged jets in data, overlayed with distributions from different flavors (normalized to the fractions from the SECVTX mass fit) (pdf,gif).