The impact of top-quark modelling on the exclusion limits in $$\varvec{t{\bar{t}}}+\text {DM}$$ t t ¯ + DM searches at the LHC
Abstract New Physics searches at the LHC rely very heavily on the precision and accuracy of Standard Model background predictions. Applying the spin-0 s-channel mediator model, we assess the importance of properly modelling such backgrounds in $$t{\bar{t}}$$ t t ¯ associated Dark Matter production....
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| Main Authors: | , |
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| Format: | article |
| Language: | EN |
| Published: |
SpringerOpen
2021
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| Subjects: | |
| Online Access: | https://doaj.org/article/da6eab9a0d1f4ea8b4bb078256952a2e |
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| Summary: | Abstract New Physics searches at the LHC rely very heavily on the precision and accuracy of Standard Model background predictions. Applying the spin-0 s-channel mediator model, we assess the importance of properly modelling such backgrounds in $$t{\bar{t}}$$ t t ¯ associated Dark Matter production. Specifically, we discuss higher-order corrections and off-shell effects for the two dominant background processes $$t{\bar{t}}$$ t t ¯ and $$t{\bar{t}}Z$$ t t ¯ Z in the presence of extremely exclusive cuts. Exclusion limits are calculated for state-of-the-art NLO full off-shell $$t{\bar{t}}$$ t t ¯ and $$t{\bar{t}}Z$$ t t ¯ Z predictions and compared to those computed with backgrounds in the NWA and / or at LO. We perform the same comparison for several new-physics sensitive observables and evaluate which of them are affected by the top-quark modelling. Additionally, we make suggestions as to which observables should be used to obtain the most stringent limits assuming integrated luminosities of 300 fb $$^{-1}$$ - 1 and 3000 fb $$^{-1}$$ - 1 . |
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