Ansgar Denner

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We have calculated the complete O(α) and O(αs) radiative corrections to the Higgsproduction process e+e− → tt̄H in the Standard Model. This process is particularly interesting for the measurement of the top-quark Yukawa coupling at a future e+e− collider. The calculation of the O(α) corrections is described in some detail including, in particular, the(More)
The radiative corrections of the strong and electroweak interactions are calculated at next-to-leading order for Higgs-boson production in the weak-boson-fusion channel at hadron colliders. Specifically, the calculation includes all weak-boson fusion and quark– antiquark annihilation diagrams to Higgs-boson production in association with two hard jets,(More)
The associate production of Higgs bosons with W or Z bosons, known as Higgs-strahlung, is an important search channel for Higgs bosons at the hadron colliders Tevatron and LHC for low Higgs-boson masses. We refine a previous calculation of next-to-leading-order electroweak corrections (and recalculate the QCD corrections) upon including the leptonic decay(More)
We present new methods for the evaluation of one-loop tensor integrals which have been used in the calculation of the complete electroweak one-loop corrections to ee → 4 fermions. The described methods for 3-point and 4-point integrals are, in particular, applicable in the case where the conventional Passarino–Veltman reduction breaks down owing to the(More)
2 On-Shell W-Pair Production and W Decay 6 2.1 Notation and conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Lowest order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3 Radiative corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.3.1 Radiative electroweak O(α)(More)
A new method for the reduction of one-loop tensor 5-point integrals to related 4point integrals is proposed. In contrast to the usual Passarino–Veltman reduction and other methods used in the literature, this reduction avoids the occurrence of inverse Gram determinants, which potentially cause severe numerical instabilities in practical calculations.(More)
Application of the background-field method yields a gauge-invariant effective action for the electroweak Standard Model, from which simple QED-like Ward identities are derived. As a consequence of these Ward identities, the background-field Green functions are shown to possess very desirable theoretical properties. The renormalization of the Standard Model(More)
The first calculation of the next-to-leading-order electroweak corrections to Z-boson + jet hadroproduction including leptonic Z-boson decays is presented, i.e. to the production of a charged lepton–anti-lepton final state in association with one hard jet at the LHC and the Tevatron. The Z-boson resonance is treated consistently using the complex-mass(More)
The process pp → tt̄bb̄ + X represents a very important background reaction to searches at the LHC, in particular to tt̄H production where the Higgs boson decays into a bb̄ pair. A successful analysis of tt̄H at the LHC requires the knowledge of direct tt̄bb̄ production at next-to-leading order in QCD. We take the first step in this direction upon(More)