We compute the hadronic production of top-antitop pairs in association with a Higgs boson at next-to-leading-order QCD, including the decay of the top and antitop quark into bottom quarks and leptons. Our computation is based on full leading and next
-to-leading-order matrix elements for $e^+ u_e mu^-bar{ u}_mu b bar{b} H(j)$ and includes all non-resonant contributions, off-shell effects and interferences. Numerical results for the integrated cross section and several differential distributions are given for the LHC operating at 13 TeV using a fixed and a dynamical factorization and renormalization scale. The use of the dynamical instead of the fixed scale improves the perturbative stability in high-energy tails of most distributions, while the integrated cross section is hardly affected differing by only about one per cent and leading to the same K factor of 1.17.
State-of-the-art predictions for the Higgs-boson production cross section via gluon fusion and for all relevant Higgs-boson decay channels are presented in the presence of a fourth Standard-Model-like fermion generation. The qualitative features of t
he most important differences to the genuine Standard Model are pointed out, and the use of the available tools for the predictions is described. For a generic mass scale of 400-600 GeV in the fourth generation explicit numerical results for the cross section and decay widths are presented, revealing extremely large electroweak radiative corrections, e.g., to the cross section and the Higgs decay into WW or ZZ pairs, where they amount to about -50% or more. This signals the onset of a non-perturbative regime due to the large Yukawa couplings in the fourth generation. An estimate of the respective large theoretical uncertainties is presented as well.
We present an update of the branching ratios for Higgs-boson decays in the Standard Model. We list results for all relevant branching ratios together with corresponding uncertainties resulting from input parameters and missing higher-order correction
s. As sources of parametric uncertainties we include the masses of the charm, bottom, and top quarks as well as the QCD coupling constant. We compare our results with other predictions in the literature.
Radiative corrections of strong and electroweak interactions are presented at next-to-leading order for the production of a Higgs boson plus two hard jets via weak interactions at the LHC. The calculation includes all weak-boson fusion and quark-anti
quark annihilation diagrams as well as the corresponding interferences. The electroweak corrections, which are discussed here for the first time, reduce the cross sections by 5%, and thus are of the same order of magnitude as the QCD corrections. As argued in previous papers, where s-channel diagrams and interferences were neglected, the QCD corrections connected to interference effects are small.
