Higgs production in association with off-shell top-antitop pairs at NLO EW and QCD at the LHC

Abstract

We present NLO electroweak corrections to Higgs production in association with off-shell top-antitop quark pairs. The full process mathrm{pp}to {mathrm{e}}^{+}{nu}_{mathrm{e}}{mu}^{-}{overline{nu}}_{mu}mathrm{b}overline{mathrm{b}}mathrm{H} is considered, and hence all interference, off-shell, and non-resonant contributions are taken into account. The electroweak corrections turn out to be below one per cent for the integrated cross section but can exceed 10% in certain phase-space regions. In addition to its phenomenological relevance, the computation constitutes a major technical achievement as the full NLO virtual corrections involving up to 9-point functions have been computed exactly. The results of the full computation are supported by two calculations in the double-pole approximation. These also allow to infer the effect of off-shell contributions and emphasise their importance especially for the run II of the LHC. Finally, we present combined predictions featuring both NLO electroweak and QCD corrections in a common set-up that will help the experimental collaborations in their quest of precisely measuring the aforementioned process.