Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 84: Associated Higgs production and Higgs quantum numbers II

T 84.6: Vortrag

Donnerstag, 18. März 2021, 17:15–17:30, Ti

Improvements of the MVA classifiers for the ttH(bb) analysis in the dilepton channel with full Run2 data in the CMS experiment — •Angela Giraldi — CMS DESY, Hamburg, Germany

In the Standard Model (SM), the Higgs boson couples to fermions with a Yukawa-type interaction and a strength proportional to the fermion mass. The associated production of a Higgs boson with a top-quark pair (ttH) is therefore the best direct probe of the top-Higgs Yukawa coupling, a vital element to verify the SM nature of the Higgs boson. In the SM, the Higgs boson decays into b-quark-antiquark pair with the largest branching fraction, and is thus experimentally attractive as a final state. The dominant background contributions arise from tt+jets production, and in particular the ttbb background is irreducible with respect to ttH, H→ bb. To better enhance the sensitivity, the signal is extracted exploiting multivariate analysis (MVA) techniques.

This talk focuses on the analysis of the ttH, H→ bb process in final states with two leptons using proton-proton data collected by the CMS experiment at the LHC during 2016-2018 at √s = 13 TeV. The possibility to critically increase the sensitivity to the ttH signal is investigated using machine learning approaches. Detailed studies on the optimization and performance of MVA discriminants trained using Artificial Neural Networks are presented for the first time in this final state.