Top Cross Section with Soft Electron Tags Public Page

SLT_e Top Cross Section with SLT_e Tags: Public Webpage

The SLT_e is a soft electron tagger designed to identify electrons that originate from the semi-leptonic decay of heavy flavor jets. We use conversion electrons and tracks in generic jets from data to parameterize the electron and fake electron tagging rate in MC. We also implement a special conversion filter to reject electrons from conversion removal. We have used it to tag b-jets associated with top pair production. We measure a top cross section of:

σ_tt (pb) = 7.8 ± 2.4 (stat) ± 1.5 (syst) ± 0.5 (lumi)

Authors

John Paul Chou (Harvard)
Melissa Franklin (Harvard)
Sebastian Grinstein (Harvard)

Click here for the public note documenting our method.

Click here to link to the internal webpage.

Plots and Tables for the SLT_e Tagger

Tagging efficiency as a function of P_T of the SLT_e tagger for conversion electrons. On the left is the breakdown of each component of the tagger. On the right is the total efficiency for all three operating points (tag levels).

Tagging efficiency as a function of P_T of the SLT_e tagger for fake electrons modeled by tracks in generic jets. On the left is the breakdown of each component of the tagger. On the right is the total efficiency for all three operating points (tag levels).

Conversion removal efficiency scale factor measurement in the generic jet datasets (jet20/50/70/100) as a function of the track P_T. This demonstrates the reliablity of the SF measurement technique.

Prediction of the Fake Matrix in the jet20/50/70/100 samples using the loosest operating point of the SLT_e tagger. The distribution is as a function of corrected Jet E_T. This demonstrates that the Fake Matrix predicts the fake electron tagging rate well both above and below the jet trigger threshold.

Predicted and measured SLT_e tagging efficiency in a bb sample. The sample is constructed out of di-jet events. The primary jet is double-tagged with a loose secondary vertex tag and an 8 GeV electron or muon. The "away" jet is tagged with a tight secondary vertex tag. The SLT_e efficiency is measured in the "away" jet in both data and MC. In MC, the tag breakdown is shown in terms of electrons from HF, electrons from conversions, and fake electrons.

P_T distribution of tags in the aforementioned bb sample. On the left is shown tags with an 8 GeV electron and on the right is shown tags with an 8 GeV Muon. An additional breakdown is shown of the sample when the two leptons (one the SLT_e tag, and on the 8 GeV lepton) have the same and opposite charge.