Sarah Budd (a), Robin Erbacher (b), Ford Garberson (c), Chris Hill (c), Daniel Jeans (d),
Taichi Kubo (e), Yoshiaki Kusakabe (f), Junji Naganoma (f), Christopher Neu (g), Jason
Nielsen (h), Daniel Sherman (i), Anyes Taffard (a), Masubuchi Tatsuya (e), Weiming Yao (h)
(a) University of Illinois, (b) UC Davis, (c) UCSB, (d) Roma, (e) Tsukuba,
(f) Waseda, (g) Penn, (h) LBNL, (i) Harvard
| We measured the ttbar pair production cross section in the lepton plus jets channel with >=1 and >= 2 secondary vertex tag using a dataset of ~700 pb-1 of proton-antiproton collisions at root(s)=1.96 TeV. We require an isolated electron or muon with transverse momentum above 20 GeV, missing transverse energy greater than 20 GeV and three or more jets with transverse energy above 15 GeV. In addition, we require that one or more of the jets are tagged with a displaced secondary vertex, indicating the presence of heavy flavor in the jet. In order to further reduce the dominant backgrounds in the >=1 b-tag sample, we require HT>200 GeV, where HT is the scalar sum of the lepton pT, jet ET, and missing ET. The signal expectation is determined from a simulation that assumes the top mass to be 175 GeV/c2. |
| Results W + >=3 jets in ~ 700 pb-1 | |
| Cross Section with >=1 b-tag with HT >200 GeV | 8.2 ± 0.6 (stat.) ± 1.0 (sys.) |
| Cross Section with >=2 b-tag | 8.8 +1.2 -1.1 (stat.) +2.0 -1.3 (sys.) |
Public Note
Event display (Comming Soon)
| Plots for talks The gif version of the plot can be obtained with right-click and "save image as" |
|
 The
expected number of W+jets tagged events categorized by source (stack
histograms) and the total number from data (points) binned in number of
jets. The top prediction is scaled to our measured value of 8.2 pb. The
cross section measurement is only based on events with 3 or more jets.
eps |
 The
expected number of W+jets double-tagged events categorized by source
(stack histograms) and the total number from data (points) binned in
number of jets. The top prediction is scaled to our measured value of
8.8 pb. The cross section measurement is only based on events with 3 or more jets.
|
 Summary of the background estimate and the number of data candidates for W+jets events with at least one b-tag.
eps |
 Summary of the background estimate and the number of data candidates for W+jets events with at least two b-tag.
eps |
 Summary of the source of systematic uncertainties
|
 The
expected number of W+>=3jets tagged events categorized by source (stacked
histograms) and the total number from data (points) binned in HT,
the scalar sum of transverse energies.
The top prediction is scaled to our measured value of 8.4 pb (measured cross section without applying the HT cut). We cut at 200 GeV in order to reduced the dominant background sources.
|
 The
expected number of W+>=3jets tagged events categorized by source (stacked
histograms) and the total number from data (points) binned in missing Et.
The top prediction is scaled to our measured value of 8.2 pb.
eps |
 The
expected number of W+>=3jets tagged events categorized by source (stacked
histograms) and the total number from data (points) binned in tagged jet Et.
The top prediction is scaled to our measured value of 8.2 pb.
|
 |
 The expected number of W+>=3jets tagged events categorized by source (stacked histograms) and the total number from data (points) binned in tagged jet detector phi. The top prediction is scaled to our measured value of 8.2 pb. |
 The
expected number of W+>=3jets tagged events categorized by source (stacked
histograms) and the total number from data (points) binned in electron Et.
The top prediction is scaled to our measured value of 8.2 pb.
eps |
 The
expected number of W+>=3jets tagged events categorized by source (stacked
histograms) and the total number from data (points) binned in muon Pt.
The top prediction is scaled to our measured value of 8.2 pb.
|
 |
 |
 |
 |
 |
 |