A search for W bb and W Higgs production in ppbar collisions at sqrt(s)=1.96 TeV

TL;DR

A search for Wbb production in pp collisions at sqrt[s]=1.96 TeV in events containing one electron, an imbalance in transverse momentum, and two b-tagged jets finds upper limits on WH production of 9.0-12.2 pb for Higgs-boson masses of 105-135 GeV.

Abstract

We present a search for W b \bar{b} production in p \bar{p} collisions at sqrt{s}=1.96 TeV in events containing one electron, an imbalance in transverse momentum, and two b-tagged jets. Using 174 pb-1 of integrated luminosity accumulated by the D0 experiment at the Fermilab Tevatron collider, and the standard-model description of such events, we set a 95% C.L. upper limit on W b \bar{b}$ production of 6.6 pb for b quarks with transverse momenta p_T^b > 20 GeV and b \bar{b} separation in pseudorapidity-azimuth space Delta R_bb > 0.75. Restricting the search to optimized b \bar{b} mass intervals provides upper limits on $WH$ production of 9.0$-$12.2 pb, for Higgs-boson masses of 105$-$135 GeV.

Figures (4)

• Figure 1: Distribution of the dijet invariant mass of $W+2$ jets events, compared with cumulative contributions from the QCD background (derived from data), the simulation of $W+$jets events and the other SM backgrounds, which are small before $b$ tagging. Uncertainties on the simulation from systematics of the jet energy scale are indicated by the hatched bands. The simulated contributions are normalized to the integrated luminosity of the data.
• Figure 2: Distribution of the dijet invariant mass for $W+2$ jets events, when at least one jet is $b$ tagged, compared to expectation (cumulative). The other SM backgrounds include single-top events. The simulated contributions are normalized to the integrated luminosity of the data.
• Figure 3: Distribution of the dijet invariant mass for $W+2~b$-tagged events, compared to expectation (cumulative). The simulated contributions are normalized to the integrated luminosity of the data. The expectation for a 115 GeV Higgs boson from $WH$ production is also shown.
• Figure 4: 95% C.L. upper limit on $\sigma(p\bar{p} \rightarrow WH) \times BR(H\rightarrow b\bar{b})$ compared to the SM expectation at $\sqrt{s}=1.96$ TeV, and to CDF results cdfsearch, which were obtained at $\sqrt{s}=1.8$ TeV. The predicted $WH$ cross section at 1.96 TeV is approximately 15% larger than that at 1.8 TeV.