Related papers: Non-forward double Pomeron exchange in QCD
The Pomeron loop amplitude and the amplitude for the diagram with any general number of loops is derived in the QCD dipole approach. It was found that the major contribution to the amplitude of an arbitrary Pomeron enhanced diagram, is…
We study two-photon exchange (TPE) in the elastic electron-nucleon scattering at high Q^2 in the framework of pQCD. The obtained TPE amplitude is of order alpha/alpha_s with respect to Born approximation. Its shape and value are sensitive…
We calculate the leading nonperturbative contributions to the effective Wilson coefficient of the four-fermion operators arising from the QCD penguin, and we demonstrate how the usual perturbative one loop contribution is augmented by…
Collider experiments have recently measured the production cross section of hard jets separated by a rapidity gap as a function of transverse momentum and gap size. We show that these measurements reveal the relative frequencies for the…
An efficient numerical algorithm to evaluate one-loop amplitudes using tensor integrals is presented. In particular, it is shown by explicit calculations that for ordered QCD amplitudes with a number of external legs up to 10, its…
The main goal of the paper is to show that we can treat the $1/N_c$ QCD corrections in the Pomeron calculus. We develop the one dimensional model which is a simplification of the QCD approach that includes $\pom \to 2 \pom$, $2 \pom \to…
We complete the calculation of the QCD penguin amplitude at next-to-next-to-leading order in the QCD factorization approach to non-leptonic B-meson decays. This provides the last missing piece in the computation of the QCD correction to…
We derive an evolution equation describing the high energy behavior of the cross section for the single diffractive dissociation in deep inelastic scattering on a hadron or a nucleus. The evolution equation resums multiple BFKL pomeron…
A Pomeron-exchange model of exclusive electroproduction of $\rho$-mesons is examined using a dressed-quark propagator. It is shown that by representing the photon-$\rho$-meson-Pomeron coupling by a nonperturbative, confined-quark loop, one…
Onium-onium scattering at high energy is used to illustrate a dipole picture of high energy hard scattering in the large $N_c$ limit. Single and double BFKL pomeron exchanges are calculated in the leading logarithmic approximation. An…
We compute the one-loop QCD amplitude for the process gg-->Q\bar{Q} in dimensional regularization through order \epsilon^2 in the dimensional regulator and for arbitrary quark mass values. This result is an ingredient of the NNLO…
We present a novel analysis of diffractive DIS data, in which the input parton distributions of the Pomeron are parameterised using perturbative QCD expressions. In addition to the usual two-gluon model for the perturbative Pomeron, we…
In the supersymmetric extension of the Standard Model we derive the two-loop QCD corrections to the scalar quark contributions to the electroweak precision observables entering via the rho parameter. A very compact expression is derived for…
We compute the order alpha_s^2 corrections to the one particle inclusive electroproduction cross section of hadrons with non vanishing transverse momentum. We compare our results with H1 data on forward production of pi^0, and conclude that…
In this talk we report on recent calculation of high energy baryon scattering amplitudes in QCD. Elastic baryon impact factors for two, three and four gluons are presented and their energy evolution is described that incorporates unitarity…
Two-loop four-gluon N=4 susy amplitudes are evaluated via cutting techniques as a testing ground for QCD. A conjecture for four-point amplitudes to all loop orders is described. We also present a new conjecture for the leading-color part of…
In the framework of analytic approach to QCD the nonperturbative contributions in running coupling of strong interaction up to 4-loop order are obtained in an explicit form. For all $Q>\Lambda$ they are shown to be represented in the form…
We investigate the soft behavior of QCD amplitudes involving multiple Wilson lines and derive compact analytic expressions for double soft gluon and double soft quark emissions at one loop. The color correlations of the soft current exhibit…
We present an explicit expression for a particular $n$-gluon two loop scattering partial amplitude. Specifically we present an analytic form for the single trace $N_c$ independent colour partial amplitude for the case where all external…
We calculate two-photon exchange amplitude for the elastic electron-proton scattering in the framework of dispersion relations. The imaginary part of the amplitude is determined by unitarity. Since in the unitarity relation intermediate…