Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 84: Associated Higgs production and Higgs quantum numbers II

T 84.4: Talk

Thursday, March 18, 2021, 16:45–17:00, Ti

Measurement of the ttH production cross-section with H→ bb in the boosted topology with the ATLAS detector — •Eftychia Tzovara, Lucia Masetti, Doga Elitez, Asma Hadef, Andriani Panagi, and Alexander Basan — JGU Mainz, Germany

Studying the coupling of the Higgs boson to the top quark is of particular interest, since it could be sensitive to effects of physics beyond the SM. The Higgs production in association with a top-quark pair is the most favorable for a direct measurement of the top Yukawa coupling. The decay to a b-quark pair has the largest branching fraction. This analysis aims at events in which one of the top quarks decays semi-leptonically, producing an electron or a muon. In the single-lepton channel, the boosted topology, targets events with a Higgs and/or a hadronically decaying top produced at high transverse momentum.

Due to the highly complex final state and the large SM backgrounds, the reconstruction of the Higgs becomes a complicated task. As a result, measuring the signal strength in this process is challenging. The ultimate goal is to constrain the background events of the boosted channel in order to maximise the statistical significance of the measurement. For this purpose, multivariate techniques are used to discriminate between signal and background events, in particular from tt + jets production. In this talk, the challenges of this decay channel and the suppression of the background processes will be discussed. Finally, the measurement of the ttH(bb) cross-section, using the full LHC run-2 data, as well as further improvements on the boosted channel, will be presented.