Abstract
We report on the calculation of the next-lo-leading order QCD corrections to Higgs boson production and decay in association with top quarks. We consider leptonic decays of top quarks leading to the hadronic process pp → e+νeμ− overline{nu} μb overline{b} H(H → X) at the LHC with sqrt{s} = 13 TeV. All resonant as well as non-resonant Feynman diagrams, interferences and off-shell effects are included for the top quark and W gauge boson. Decays of the Higgs boson, on the other hand, are included in the narrow-width approximation. Specifically, we consider Higgs boson decays into b overline{b} , τ+τ−, γγ and e+e−e+e−. Numerical results are given at the integrated and differential fiducial level for various factorisation and renormalisation scale choices and different PDF sets. We study the main theoretical uncertainties that are associated with neglected higher order terms in the perturbative expansion and with different parametrisations of the PDFs. Furthermore, we examine the size of the off-shell effects by an explicit comparison to the calculation in the full narrow-width approximation. Finally, the impact of the contributions induced by the bottom-quark parton density is investigated.
Highlights
We report on the calculation of the next-lo-leading order QCD corrections to Higgs boson production and decay in association with top quarks
We report on the computation of the next-to-leading order (NLO) QCD corrections to offshell ttH production in the di-lepton top quark decay channel with Higgs boson decays in the narrowwidth approximation (NWA)
At NLO, we find that, for the fixed scale choice, scale uncertainties can be as high as 100% and even negative values are included in the uncertainty bands
Summary
We are able to include the production and decays of the Higgs boson in association with top quarks using the NWA for the Higgs boson at NLO in QCD, while keeping full offshell effects for top quarks and for all other unstable particles This approach is very well justified as we argued before. As we consider decays of a scalar particle, no spin information is transferred from the production to the decay stage which further warrants the use of the LHEFs. The phase-space integration for Higgs boson decay products is performed using our own implementation of the algorithm outlined in ref. The bottom quark mass is still neglected throughout the calculation This allows us to resum large initial state collinear logarithms into PDFs. In order to keep a non-zero coupling between the Higgs boson and bottom quarks, we keep Yb non-zero in the decay stage and perform the renormalisation in the MS scheme.
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