Searcharxiv⌕ Search

arXiv subjects

D. Wackeroth

Publications and source records attributed to D. Wackeroth.

70 records · Page 4Linked to original sources
arXiv2000

Electroweak radiative corrections to e+e- --> WW --> 4fermions in double-pole approximation -- the RACOONWW approach

We calculate the complete O(alpha) electroweak radiative corrections to e+e- --> WW --> 4f in the electroweak Standard Model in the double-pole approximation. We give analytical results for the non-factorizable virtual corrections and express the factorizable virtual corrections in terms of the known corrections to on-shell W-pair production and W decay. The calculation of the bremsstrahlung corrections, i.e. the processes e+e- --> 4f+gamma in lowest order, is based on the full matrix elements. The matching of soft and collinear singularities between virtual and real corrections is done alternatively in two different ways, namely by using a subtraction method and by applying phase-space slicing. The O(alpha) corrections as well as higher-order initial-state photon radiation are implemented in the Monte Carlo generator RACOONWW. Numerical results of this program are presented for the W-pair-production cross section, angular and W-invariant-mass distributions at LEP2. We also discuss the intrinsic theoretical uncertainty of our approach.

hep-ph↗
arXiv2000

Radiative corrections to e+e- --> WW --> 4f with RACOONWW

RACOONWW is the first Monte Carlo generator for e+e- --> WW --> 4f(+gamma) that includes the electroweak O(alpha) radiative corrections in the double-pole approximation completely. Some numerical results for LEP2 energies are discussed, and the predictions for the total W-pair cross section are confronted with LEP2 data.

hep-ph↗
arXiv2000

Four-Fermion Production in Electron-Positron Collisions

This report summarises the results of the four-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the calculation of four-fermion processes in electron-positron collisions at LEP-2 centre-of-mass energies are presented, concentrating on predictions for four main reactions: W-pair production, visible photons in four-fermion events, single-W production and Z-pair production. Based on a comparison of results derived within different approaches, theoretical uncertainties on these predictions are established.

hep-ph↗
arXiv2000

Precise predictions for W-pair production at LEP2 with RACOONWW

RACOONWW is the first Monte Carlo generator for e+e- --> WW --> 4f(+gamma) that includes the electroweak O(alpha) radiative corrections in the double-pole approximation completely. Some numerical results for LEP2 energies are discussed, and the predictions for the total W-pair cross section are confronted with LEP2 data.

hep-ph↗
arXiv1999

W-pair production at future e+e- colliders: precise predictions from RACOONWW

We present numerical results for total cross sections and various distributions for e+e- --> WW --> 4f(+gamma) at a future 500GeV linear collider, obtained from the Monte Carlo generator RACOONWW. This generator is the first one that includes O(alpha) electroweak radiative corrections in the double-pole approximation completely. Owing to their large size the corrections are of great phenomenological importance.

hep-ph↗
arXiv1999

Four-fermion production with RACOONWW

RACOONWW is an event generator for e+e- --> WW --> 4fermions(+gamma) that includes full tree-level predictions for e+e- --> 4f and e+e- --> 4f+gamma as well as O(alpha) corrections to e+e- --> 4f in the so-called double-pole approximation. We briefly sketch the concept of the calculation on which this generator is based and present some numerical results.

hep-ph↗
arXiv1999

O(alpha) corrections to e+e- --> WW --> 4fermions(+gamma): first numerical results from RACOONWW

First numerical results of the Monte Carlo generator RACOONWW for e+e- --> WW --> 4fermions(+gamma) in the electroweak Standard Model are presented. This event generator is the first one that includes O(alpha) electroweak radiative corrections in the double-pole approximation completely. We briefly describe the strategy of the calculation and give numerical results for total cross sections, including CC03, and various distributions.

hep-ph↗
arXiv1999

Radiative corrections to e^+e^- -> WW -> 4 fermions

The structure of the double-pole approximation for the O(alpha) corrections to e^+e^- -> WW -> 4 fermions is described, and some results are presented. Moreover, results on full tree-level predictions for $e^+e^- -> WW -> 4 fermions + gamma are given.

hep-ph↗
arXiv1999

Predictions for all processes e^+e^- -> 4 fermions + gamma

The complete matrix elements for e^+ e^- -> 4f and e^+ e^- -> 4f + gamma are calculated in the Electroweak Standard Model for polarized massless fermions. The matrix elements for all final states are reduced to a few compact generic functions. Monte Carlo generators for e^+ e^- -> 4f and e^+ e^- -> 4f + gamma are constructed. We compare different treatments of the finite widths of the electroweak gauge bosons; in particular, we include a scheme with a complex gauge-boson mass that obeys all Ward identities. The detailed discussion of numerical results comprises integrated cross sections as well as photon-energy distributions for all different final states.

hep-ph↗
arXiv1998

Loop-induced SUSY Effects in Strong Top Pair Production

We present some results of the calculation of MSSM one-loop contributions to strong $t \bar t$ production in hadronic collisions. Here we concentrate on the MSSM electroweak-like O(α) and SQCD O(α_s) corrections to the main production mechanism at the Fermilab Tevatron $p \bar p$ collider, $q\bar q\to g \to t \bar t$. We give results for the total $t \bar t$ production rate and for parity violating asymmetries in the production of left and right handed top quark pairs.

hep-ph↗
arXiv1998

Electroweak Radiative Corrections to W Boson Production in Hadronic Collisions

The O(α) electroweak radiative corrections to the process pp, ppbar\to W \to\ell^\pmν(\ell=e,μ) are calculated. The O(α) corrections can be decomposed into separately gauge invariant contributions to the W boson production and decay processes. Factorizing the collinear singularity associated with initial state photon radiation into the parton distribution functions, we find that initial state corrections have a significantly smaller effect than final state radiative corrections. We study in detail the effect of electroweak radiative corrections on a number of interesting observables: the W transverse mass distribution, the W to Z transverse mass ratio, the charge asymmetry of leptons in W\to\ellνdecays, as well as the W production cross section and the W to Z cross section ratio. We also investigate how experimental lepton identification requirements change the effect of the electroweak corrections.

hep-ph↗
arXiv1997

MSSM Radiative Corrections to the Top Pair Production Processes at Hadron Colliders

We calculate the MSSM $O(α)$ corrections to the main production processes of strong top pair production at the upgraded Tevatron and at the LHC. In exploring the potential of future hadron colliders for performing electroweak precision physics we study their effects on the total hadronic cross sections, the invariant $t\bar t$ mass distributions and give first results for parity violating asymmetries in the production of left and right handed top quarks.

hep-ph↗
arXiv1997

Top Pair Production at Hadron Colliders in non-minimal Standard Models

The cross section of top pair production in hadronic collisions to O(alpha α_s^2) is calculated within the General 2-Higgs-Doublet Model and the Minimal Supersymmetric Standard Model. At the parton level the O(alpha) one-loop corrections to the main production mechanisms, quark-antiquark annihilation and gluon fusion, significantly modify the Born-cross sections: in the threshold region \sqrt{\hat s}>~2 m_t they are enhanced up to 50 % and with increasing cm energy \sqrt{\hat s}, they can be reduced by up to the same order of magnitude. In a wide range of the parameter space of the models under consideration the observable hadronic cross sections for top pair production at the Tevatron and at the LHC are typically reduced by several percent (<~10 %) compared to the lowest order result. In special regions of the parameter space, that is in the vicinity of the threshold for the top quark decay t \to b H^+ ; \tilde t \tilde χ^0, the radiative corrections are considerably enhanced, comparable in size to QCD effects.

hep-ph↗