Hamburg 2016 – scientific programme

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T: Fachverband Teilchenphysik

T 59: Top Quark III (tt+X)

T 59.1: Talk

Tuesday, March 1, 2016, 16:45–17:00, VMP9 HS

Cross Section Measurement of the Bottom-Quark-Pair Associated Top-Quark-Pair Production in the Semi-Leptonic Channel with the CMS Experiment. — •Fabian Heidemann, Martin Erdmann, and Robert Fischer — III. Physikalisches Institut A, RWTH Aachen University

We present a cross section measurement of the top-quark-pair-production with two bottom quarks which is the dominant background process to top-quark-pair associated Higgs Boson production. The semi-leptonic channel of top-quark decays is used due to its combination of a relatively large branching ratio and small QCD contamination. The analysis method relies on Standard Model Monte Carlo simulations of all relevant physics processes. Template distributions are created with Boosted Decision Tree classifiers on the simulated data. Subsequently, the composition of these templates is fitted to the data distribution to obtain the signal strength relative to the Standard Model prediction. A Bayesian interference method is used to perform the fit, in which systematic uncertainties are incorporated as nuisance parameters.