Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 9: Associated Higgs production and Higgs quantum numbers I

T 9.9: Vortrag

Montag, 15. März 2021, 18:00–18:15, Ti

ANN based jet assignment in the simultaneous inclusive cross-section measurement of tt+H/tt+Z in the semi-leptonic channel targeting bb decays at the CMS experiment — •Lukas Armbruster, Ulrich Husemann, and Jan van der Linden — Institut für Experimentelle Teilchenphysik (ETP), Karlsruher Institut für Technologie (KIT)

Higgs production in association with a top quark-antiquark pair (tt+H) is one of the main Higgs production channels at the Large Hadron Collider (LHC). Additionally, the subsequent decay of the Higgs boson into a pair of bottom quarks (H→ bb) is one of the most favored decay channels, due to the fact that b-jets are well distinguishable from other jet background (b-tagging).

This is why this study’s focus is on the tt+H decay chain. However, there occur some very similar processes, mainly the production of a Z boson in association with a top quark-antiquark pair (tt+Z) and the associated production of bottom quarks with a pair of top quarks (tt+bb). Since these processes are very similar to the tt+H → bb process, it is of vital importance to discriminate these from each other.

One essential step for the discrimination of these processes is the correct assignment of the occurring jets to a certain hypothesis (e.g. bb from Z boson) for any event. The jet assignment is quite challenging, since there are many (b-)jets in a single event and therefore numerous jet combinations are possible.

In this talk the strategy of jet assignment via Artificial Neural Networks (ANNs) is presented, in contrast to traditional χ²-methods.