Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 79: Top quark production III

T 79.3: Talk

Thursday, March 18, 2021, 16:30–16:45, Td

Assignment methods for b jets in tt+bb processes in the lepton+jets channel at the CMS experiment. — •Emanuel Pfeffer, Ulrich Husemann, and Jan van der Linden — Institut für Experimentelle Teilchenphysik (ETP), Karlsruher Institut für Technologie (KIT)

The associated production of bottom quarks with a top quark-antiquark pair is a large irreducible background in measurements of ttH in H→bb decays at the Large Hadron Collider which are important to test the Standard Model and to constrain Physics beyond the Standard Model. Additionally, the process itself is of particular interest due to its multiscale QCD nature. In order to better understand the process, the b jets must be assigned to their origin. In the final state of a tt+bb event it is unknown which b jets originate from top quark decays and which b jets are not associated with the top quarks. Therefore, the question should be answered: Which methods allow for an assignment of the b jets to their origin and how accurate is the assignment? The talk gives an overview of different strategies to assign the b jets and evaluates the accuracies of the methods. These methods range from straightforward observables to sophisticated reconstructions with deep neural networks.