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T: Fachverband Teilchenphysik

T 77: Suche nach dunkler Materie IV

T 77.7: Vortrag

Donnerstag, 22. März 2018, 18:15–18:30, Philo-HS5

Improvement of Dark Matter searches with the ATLAS detector using dijet production to constrain systematic uncertainties — •Sebastian Mario Weber — Kirchhoff-Institut für Physik, Heidelberg, Deutschland

The composition and origin of Dark Matter (DM) remains one of the most important questions of modern physics and could be an avenue to phenomena beyond the Standard Model. A typical signature for direct DM production at hadron colliders is large missing transverse energy (E_T) in association with one or more energetic jets.

An irreducible background to this signature is the decay of the Z boson to neutrinos (Z→νν +jets). For searches, a very precise control of this background in the signal region is necessary. This is typically achieved using a control region enriched with Z→ l⁺l⁻ +jets production. The main limitation of this approach is the small cross section of Z→ l⁺l⁻ +jets at large missing (E_T), resulting in statistical fluctuations that dominate the total uncertainty.

This talk proposes an improvement of DM searches with a new CR based on dijet production in the context of a cross section ratio measurement. The main advantage of this CR are small statistical uncertainties due to a higher cross section up to large missing E_T. The focus of this talk is the constraining power of the new CR with respect to experimental jet systematics, as well as theoretical scale variations and uncertainties of the parton density functions.