Tt̄+large missing energy from top-quark partners: A comprehensive study at next-to-leading order QCD

Radja Boughezal*, Markus Schulze

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We perform a detailed study of top-quark partner production in the tt̄ plus large missing energy final state at the LHC, presenting results for both scalar and fermionic top-quark partners in the semileptonic and dileptonic decay modes of the top quarks. We compare the results of several simulation tools: leading order matrix elements, next-to-leading order (NLO) matrix elements, leading order plus parton shower simulations, and merged samples that contain the signal process with an additional hard jet radiated. We find that predictions from leading order plus parton shower simulations can significantly deviate from NLO QCD or LO merged samples and do not correctly model the kinematics of the tt̄+ET,miss signature. They are therefore not a good framework for modeling this new physics signature. On the other hand, the acceptances obtained with a merged sample of the leading-order process together with the radiation of an additional hard jet are in agreement with the NLO predictions. We also demonstrate that the scale variation of the inclusive cross section, plus that of the acceptance, does not accurately reflect the uncertainty of the cross section after cuts, which is typically larger. We show the importance of including higher-order QCD corrections when using kinematic distributions to determine the spin of the top-quark partner.

Original languageEnglish (US)
Article number114002
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume88
Issue number11
DOIs
StatePublished - Dec 2 2013

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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