NLO QCD corrections to pp -> ttbb+X via quark anti-quark annihilation
  The process pp -> top anti-top bottom anti-bottom + X represents a very important background reaction to searches at the LHC, in particular to top anti-top H production where the Higgs boson decays into a bottom anti-bottom pair. A successful analysis of top anti-top H at the LHC requires the knowledge of direct top anti-top bottom anti-bottom production at NLO in QCD. We take the first step in this direction upon calculating the NLO QCD corrections to the subprocess initiated by quark anti-quark annihilation. 
Axel Bredenstein, Ansgar Denner, Stefan Dittmaier, Stefano Pozzorini