Next-to-leading order QCD predictions for top-quark pair production with   up to two jets merged with a parton shower
  We present differential cross sections for the production of top-quark pairs in conjunction with up to two jets, computed at next-to leading order in perturbative QCD and consistently merged with a parton shower in the Sherpa+OpenLoops framework. Top quark decays including spin correlation effects are taken into account at leading order accuracy. The calculation yields a unified description of top-pair plus multi-jet production, and detailed results are presented for various key observables at the Large Hadron Collider. A large improvement with respect to the multi-jet merging approach at leading order is found for the total transverse energy spectrum, which plays a prominent role in searches for physics beyond the Standard Model. 
Stefan H\"oche, Frank Krauss, Philipp Maierhoefer, Stefano Pozzorini,   Marek Schonherr, Frank Siegert
hep-ph