Associated production of a top-quark pair with vector bosons at NLO in QCD: impact on t t ¯ H $$ mathrm{t}overline{mathrm{t}}mathrm{H} $$ searches at the LHC

摘要

We study the production of a top-quark pair in association with one and two vector bosons, tt¯Vtt¯V and tt¯VVtt¯VV with V = γ, Z, W ±, at the LHC. We provide predictions at next-to-leading order in QCD for total cross sections and top-quark charge asymmetries as well as for differential distributions. A thorough discussion of the residual theoretical uncertainties related to missing higher orders and to parton distribution functions is presented. As an application, we calculate the total cross sections for this class of processes (together with tt¯Htt¯H and tt¯tt¯tt¯tt¯ production) at hadron colliders for energies up to 100 TeV. In addition, by matching the NLO calculation to a parton shower, we determine the contribution of tt¯Vtt¯V and tt¯VVtt¯VV to final state signatures (two-photon and two-same-sign-, three-and four-lepton) relevant for tt¯Htt¯H analyses at the Run II of the LHC.