Tobias Kasprzik

Electroweak corrections to dilepton + jet production at hadron colliders

The first calculation of the next-to-leading-order electroweak corrections to Z-bosonu2009+u2009jet 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 scheme, and all off-shell effects as well as the contributions of the intermediate photon are taken into account. The corresponding next-to-leading-order QCD corrections have also been recalculated. The full calculation is implemented in a flexible Monte Carlo code. Numerical results for cross sections and distributions of this Standard Model benchmark process are presented for the Tevatron and the LHC.

Vector-boson pair production at the LHC to \( \mathcal{O} \)(α3) accuracy

A bstractBuilding on earlier work on electroweak corrections to W-pair production, the first calculation of the full electroweak one-loop corrections to on-shell ZZ, W±Z and γγ production at hadron colliders is presented, explicitly taking into account the full vector-boson mass dependence. As a consequence, our results are valid in the whole energy range probed by LHC experiments. Until now, the electroweak corrections have only been known in dedicated high-energy approximations limited to a specific kinematic regime, in particular requiring high boson transverse momenta. Therefore, our results comprise an important and so far missing ingredient to improve on the theory predictions for these fundamental Standard-Model benchmark processes also at intermediate energies and small scattering angles, where actually the bulk of events is located. In case of Z-pair production we have also included the leptonic decays and the associated weak corrections in our analysis. For this particular channel, corrections of about −4% are observed even close to the production threshold. For hard scattering processes with momentum transfers of several hundred GeV one finds large negative corrections which may amount to several tens of percent and lead to significant distortions of transverse-momentum and rapidity distributions.

Electroweak corrections to W-boson pair production at the LHC

A bstractVector-boson pair production ranks among the most important Standard-Model benchmark processes at the LHC, not only in view of on-going Higgs analyses. These processes may also help to gain a deeper understanding of the electroweak interaction in general, and to test the validity of the Standard Model at highest energies. In this work, the first calculation of the full one-loop electroweak corrections to on-shell W-boson pair production at hadron colliders is presented. We discuss the impact of the corrections on the total cross section as well as on relevant differential distributions. We observe that corrections due to photon-induced channels can be amazingly large at energies accessible at the LHC, while radiation of additional massive vector bosons does not influence the results significantly.

Electroweak corrections to monojet production at the Tevatron and the LHC

Single-jet production with missing transverse momentum is one of the most promising discovery channels for new physics at the LHC. In the Standard Model, Z+jet production with a Z-boson decay into neutrinos leads to this monojet signature. To improve the corresponding Standard Model predictions, we present the calculation of the full next-to-leading-order (NLO) electroweak corrections and a recalculation of the NLO QCD corrections to monojet production at the Tevatron and the LHC. We discuss the phenomenological impact on the total cross sections as well as on relevant differential distributions.

Z+jet production at the LHC: Electroweak radiative corrections

The investigation of weak bosons V (V = W ± , 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 vector bosons, weak-boson production can be used to monitor and calibrate the luminosity of the collider, to constrain t he 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 corre ctions to Z(! 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.

Electroweak Precision for W+jet Production

In this talk we discuss the next-to-leading-order electroweak (EW) corrections to W-boson + jet hadroproduction [1] and compare the full result to a simple approximation assuming factorization of EW and QCD corrections for the charged-current Drell-Yan process. The W-boson resonance is treated consistently using the complex-mass scheme, and all off-shell effects are taken into account. The corresponding next-to-leading-order QCD corrections have also been recalculated. All the results are implemented in a flexible Monte Carlo code. Selected numerical results for this Standard Model benchmark process are presented for the LHC. The comparison of our result to an approximation based on the EW corrections to W-boson production without additional jets is a step towards a better understanding of the interplay between QCD and EW effects for W-boson production in general.