This document presents an interim framework in which the coupling structure of a Higgs-like particle can be studied. After discussing different options and approximations, recommendations on specific benchmark parametrizations to be used to fit the data are given.
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.
The investigation of weak bosons $V$ ($V=mathrm{W}^{pm}$, $mathrm{Z}$) produced with or without associated hard QCD jets will be of great phenomenological interest at the LHC. Owing to the large cross sections and the clean decay signatures of the ve
ctor bosons, weak-boson production can be used to monitor and calibrate the luminosity of the collider, to constrain the PDFs, or to calibrate the detector. Moreover, the $Z$+jet(s) final state constitutes an important background to a large variety of signatures of physics beyond the Standard Model. To match the excellent experimental accuracy that is expected at the LHC, we have worked out a theoretical next-to-leading-order analysis of $V$+jet production at hadron colliders. The focus of this talk will be on new results on the full electroweak corrections to $Z(to l^-l^+)$+jet production at the LHC. All off-shell effects are included in our approach, and the finite lifetime of the $Z$ boson is consistently accounted for using the complex-mass scheme. In the following, we briefly introduce the calculation and discuss selected phenomenological implications of our results.
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.
