Full NLO QCD corrections to off-shell tt bb production

In this article, we report on the computation of the next-to-leading order (NLO) QCD corrections to pp → μ− νμe + νe bbbb at the LHC, which is an irreducible background to pp → ttH (→ bb). This is the first time that a full NLO computation for a 2 → 8 process with 6 external strongly interacting partons is made public. No approximations are used, and all off-shell and interference effects are taken into account. Cross sections and differential distributions from the full computation are compared to results obtained by using a double-pole approximation for the top quarks. The difference between the full calculation and the one using the double-pole approximation is in general below 5% but can reach 10% in some regions of phase space.