Related papers: How to calculate colourful cross sections efficien…
We derive an improved prescription for the merging of matrix elements with parton showers, extending the CKKW approach. A flavour-dependent phase space separation criterion is proposed. We show that this new method preserves the logarithmic…
A measurement of W->e nu + n-jet cross sections in ppbar collisions at sqrt(s)=1.96 TeV using the Collider Detector at Fermilab in Run II is presented. The measurement is based on an integrated luminosity of 320 pb-1, and includes events…
We consider inelastic QED processes, the cross sections of which do not drop with increasing energy. Such reactions have the form of two-jet processes with the exchange of a virtual photon in the t-channel. We consider them in the region of…
We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in…
Calculations for processes involving a high multiplicity of coloured particles often employ a leading colour approximation, where only the leading terms in the expansion of the number of colours $N_c$ and the number of flavours $n_f$ are…
Standard QCD resummation techniques provide precise predictions for the spectrum and the cumulant of a given observable. The integrated spectrum and the cumulant differ by higher-order terms which, however, can be numerically significant.…
The knowledge of the exact structure of the optical system PSF enables a high-quality image reconstruction in fluorescence microscopy. Accurate PSF models account for the vector nature of light and the phase and amplitude modifications.…
The calibration QED process cross sections for experiments on planned electron-photon and photon-photon colliders for detecting the small angles scattered particles are calculated. These processes describe the creation of two jets moving…
We describe a general method of calculating the fully differential cross section for the production of jets at next-to-leading order in a hadron collider. This method is based on a `crossing' of next-to-leading order calculations with all…
I discuss how to sample the space of parton momenta in order to best perform the numerical integrations that lead to a calculation of three jet cross sections and similar observables in electron-positron annihilation.
The investigation of colour symmetries for periodic and aperiodic systems consists of two steps. The first concerns the computation of the possible numbers of colours and is mainly combinatorial in nature. The second is algebraic and…
A unified approach to total cross-sections, based on the QCD contribution to the rise with energy, is presented for the processes $pp$, $p{\bar p}$, $\gamma p, \gamma \gamma, e^+e^- \to hadrons$. For proton processes, a discussion of the…
We compare four different methods for the numerical computation of the pure gluonic amplitudes in the Born approximation. We are in particular interested in the efficiency of the various methods as the number n of the external particles…
We employ the Polyakov world-line path-integral version of QCD to identify and resum at leading perturbative order enhanced radiative gluon contributions to the Drell-Yan type ($q\bar{q}$ pair annihilation) cross-sections. We emphasize that…
The box counting method for fractal dimension estimation had not been applied to large or colour images thus far due to the processing time required. In this letter we present a fast, easy to implement and very easily expandable to any…
In the context of a subtraction method for jet cross sections at NNLO accuracy in the strong coupling, we perform the integration over the two-particle factorised phase space of the collinear-type contributions to the doubly unresolved…
We present an algorithm to evaluate the exact, tree-level matrix elements for multi-parton processes in QCD. We tested this technique, based on the recursive evaluation of the S-matrix, on processes such as gg -> n gluons and q qbar -> n…
The total cross-section and the jet cross-section differ at a proton-proton collision. The latter is divergent if arbitrarily small transverse momenta are allowed. Even with some fixed lower pt cutoff, increases the jet cross-section much…
A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass…
We present a new subtraction scheme for computing jet cross sections in electron-positron annihilation at next-to-leading order accuracy in perturbative QCD. The new scheme is motivated by problems emerging in extending the subtraction…