On the determination of the trilinear boson couplings in e^-e^+ --> lepton anti-neutrino quark anti-quark at LEPII

We present the full tree-order calculation of the process e^+e^-\to\ell\bar{\nu}_\ell\; q \bqp including the width effects in a way which is consistent with gauge invariance and high energy unitarity and which has a natural interpretation within standard perturbation theory. We also include C- and P-preserving deviations from Standard Model trilinear vector boson couplings. An analysis of the sensitivity of these channels on the trilinear couplings, using well measured angular variables of the four fermion final state, is also presented.Comment: uuencoded file, 23 pages, February 95, references adde

HELAC-PHEGAS: automatic computation of helicity amplitudes and cross sections

HELAC-PHEGAS is a FORTRAN based package that is able to compute automatically and efficiently tree-order helicity amplitudes and cross sections for arbitrary scattering processes within the standard electroweak theory and QCD. The algorithm for the amplitude computation, HELAC, exploits the virtues of the Dyson-Schwinger equations. The phase-space generation algorithm, PHEGAS, constructs all possible kinematical mappings dictated by the amplitude under consideration. Combined with mutichannel self-optimized Monte Carlo integration it results to efficient cross section evaluation.Comment: 4 pages, LaTeX, to appear in the proceedings of the VII International Workshop on Advanced Computing and Analysis Technics in Physics Research, ACAT 2000, Fermilab, October 16-20, 200

Studying Trilinear Gauge Couplings at Linear Collider Energies

We study the sensitivity of the processes `e+ e- -> lepton (l) neutrino (v) quark (u) antiquark (d)', where the lepton is an electron or a muon, on the non-standard trilinear gauge couplings (TGC), using the optimal observables method at Linear Collider energies. Our study is based on the four-fermion generator ERATO. Taking into account all possible correlations between the different trilinear gauge coupling parameters, we show that they can be measured with an accuracy of $10^{-3}$ to $10^{-4}$ for typical Linear Collider energies and luminosities.Comment: 17 pages, LaTeX, version to appear in Zeitschrift fur Physi

Two-loop Master Integrals with the Simplified Differential Equations approach

We calculate the complete set of two-loop Master Integrals with two off mass-shell legs with massless internal propagators, that contribute to amplitudes of diboson $V_1V_2$ production at the LHC. This is done with the Simplified Differential Equations approach to Master Integrals, which was recently proposed by one of the authors.Comment: 4 figures, 6 ancillary files. Version as published in JHE

The Pentabox Master Integrals with the Simplified Differential Equations approach

We present the calculation of massless two-loop Master Integrals relevant to five-point amplitudes with one off-shell external leg and derive the complete set of planar Master Integrals with five on-mass-shell legs, that contribute to many $2\to 3$ amplitudes of interest at the LHC, as for instance three jet production, $\gamma, V, H +2$ jets etc., based on the Simplified Differential Equations approach.Comment: Revised version accepted for publication in JHEP. Ancillary files with results can be downloaded from https://www.dropbox.com/s/90iiqfcazrhwtso/results.tgz?dl=