Christian Speckner

Weak radiative corrections to dijet production at hadron colliders

A bstractWe present the calculation of the most important electroweak corrections to( dijet production at the LHC and the Tevatron, comprising tree-level effects of

Next-to-leading order electroweak corrections to pp → W+W− → 4 leptons at the LHC in double-pole approximation

{\cal O}\left( {{{\alpha }_{{\rm{s}}}}\alpha ,{{\alpha }^{2}}} \right)

QCD in the color-flow representation

and weak loop corrections of

Noncommutative standard model and polarization in charged gauge boson production at the LHC

{\cal O}\left( {\alpha _{s}^{2}\alpha } \right)

A tool box for implementing supersymmetric models

. Although negligible for integrated cross sections, these corrections can reach 10−20% in the TeV range for transverse jet momenta kT. Our detailed discussion of numerical results comprises distributions in the dijet invariant mass and in the transverse momenta of the leading and subleading jets. We find that the weak loop corrections amount to about −12% and −10% for leading jets with kT ∼ 3TeV at the 14 TeV LHC and kT ∼ 800 GeV at the Tevatron, respectively. The electroweak tree-level contributions are of the same generic size and typically positive at the LHC and negative at the Tevatron at high energy scales. Generally the corrections to the dijet invariant mass distributions are smaller by at least a factor of two as compared to the corresponding reach in the kT distributions, because unlike the kT spectra the invariant-mass distributions are not dominated by the Sudakov regime at high energy scales.

Introducing an interface between FeynRules and WHIZARD

A bstractWe present the calculation of next-to-leading-order electroweak corrections to W-boson pair production at the LHC, taking off-shell effects of the W bosons and their leptonic decays into account in the framework of the so-called double-pole approximation. In detail, the lowest-order cross section and the photonic bremsstrahlung are based on full matrix elements with four-fermion final states, but the virtual one-loop corrections are approximated by the leading contributions of a systematic expansion about the resonance poles of the two W bosons. This expansion classifies the virtual corrections into factorizable and non-factorizable corrections, the calculation of which is described in detail. Corrections induced by photons in the initial state, i.e. photon-photon and quark-photon collision channels, are included and based on complete matrix elements as well. Our numerical results, which are presented for realistic acceptance cuts applied to the W-boson decay products, qualitatively confirm recent results obtained for on-shell W bosons and reveal electroweak corrections of the size of tens of percent in the TeV range of transverse momenta and invariant masses. In general, photon-photon and quark-photon induced contributions amount to 5−10% of the full differential result. Compared to previous predictions based on stable W bosons electroweak corrections, however, can change by several percent because of realistic cuts on the W-boson decay products and corrections to the decays.

Exploring the golden channel for HEIDI models using an interface between Whizard and FeynRules

A bstractFor many practical purposes, it is convenient to formulate unbroken non-abelian gauge theories like QCD in a color-flow basis. We present a new derivation of SU(N) interactions in the color-flow basis by extending the gauge group to U(N) × U(1)′ in such a way that the two U(1) factors cancel each other. We use the quantum action principles to show the equivalence to the usual basis to all orders in perturbation theory. We extend the known Feynman rules to exotic color representations (e.g. sextets) and discuss practical applications as they occur in automatic computation programs.

Production of Almost Fermiophobic Gauge Bosons in the Minimal Higgsless Model at the LHC

We study the pair production of charged gauge bosons at the LHC in a noncommutative extension of the standard model. We use angular distributions in the decays of the gauge bosons to partially reconstruct polarized cross sections. We use this, together with

Exploring compactified HEIDI models at the LHC

CP

Next-to-leading-order electroweak corrections to pp->WW->4 leptons in double-pole approximation at the LHC

considerations, to construct more sensitive observables that allow us to separate space-time from space-space noncommutativities.