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We consider the diffractive Drell-Yan process in proton-(anti) proton collisions at high energies in the color dipole approach. The calculations are performed at forward rapidities of the leptonic pair. The effect of eikonalization of the universal "bare" dipole-target elastic amplitude in the saturation regime takes into account the principal part of the gap survival probability. We present predi
We present a formalism which modifies the Mueller Dipole Model such that it incorporates energy-momentum conservation and also important colour suppressed effects. We implement our formalism in a Monte Carlo simulation and compare the results to inclusive data from HERA and the Tevatron, where we see that there is a good agreement between the data and our model.
We calculate the one-loop effective action of the SU(2) Yang-Mills theory for center-vortex configurations, both in 3D and 4D. We find that in both cases there are minima of the effective action, corresponding to vortices of the transverse size approximately 4/g(3)(2) and 1.7/Lambda((MS) over bar), respectively. The values of the effective actions at the minima are negative, suggesting that the Eu
HERA provides a unique possibility to investigate the dependence of multiple interactions on transverse interaction sizes through variation of the photon virtuality Q2. In order to observe effects of multiple interactions at Q2 substantially different from zero we have to look into regions of phase space where resolved processes dominate over direct ones. The forward jet production at small values
The Lund dipole model DIPSY is based on BFKL evolution and saturation. It can be applied to collisions between electrons, protons, and nuclei. In this paper, I present some recent results for exclusive final states in inelastic collisions, a method to generate final states in diffractive excitation, and some results for collisions with nuclei.
We add the Wess-Zumino-Witten term to the N = 3 massive nonlinear sigma model and study the leading logarithms in the anomalous sector. We obtain the leading logarithms to six loops for pi(0) -> gamma*gamma* and to five loops for y*pi pi pi. In addition we extend the earlier work on the mass and decay constant to six loops and the vector form factor to five loops. We present numerical results for
The top quark pair production and decay are considered in the framework of the smeared-mass unstable particles model. The results for total and differential cross-sections in vicinity of t (t) over bar threshold are in good agreement with the previous ones in the literature. The strategy of calculations of the higher order corrections in the framework of the model is discussed. Suggested approach
We discuss new diffractive mechanism of central exclusive production of W+W- pairs in proton-proton collisions at the LHC. We include diagrams with intermediate virtual Higgs boson as well as quark box diagrams. Several observables related to this process are calculated. Predictions for the total cross section and differential distributions in W-boson rapidity and transverse momentum as well as WW
A systematic study of the odd-intrinsic parity sector of QCD is presented. We briefly describe different applications including pi(0) -> gamma gamma decay, muonic g -2 factor and test of new holographic conjectures.
We review Buchler and Colangelo's result that leading divergences at any loop order can be calculated using only one-loop calculations and we provide an alternative proof. We then use this method to calculate the leading divergences of and thus the leading logarithmic corrections to the meson mass in the massive $O(N)$ nonlinear sigma model to five-loop order. We also calculate the all-loop result
We report lifetime measurements of the five levels in the 3d(4)(a(5)D)5s e(6)D term in Cr II at an energy around 83 000 cm(-1), and log(gf) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the pla
Based on the chiral perturbation theory, we investigate the low-energy dynamics of nucleon parton distributions. We show that in different regions of the momentum fraction x the chiral expansion is significantly different. For nucleon parton distributions these regions are characterized by x similar to 1, x similar to m(pi)/M-N and x similar to (m(pi)/M-N)(2). We derive extended counting rules for
Medium-induced gluon radiation gives rise to the strong energy loss observed in single hadron spectra in heavy ion collisions. Its angular structure, leading e.g. to intra-jet correlations, is only known for the one-gluon inclusive case. In the vacuum, properties such as angular ordering appear when considering less inclusive distributions due to destructive interference effects. We present a calc
In this contribution I want to discuss three phenomena, where effects of fluctuations are very important, multiplicity distributions, diffractive excitation, and nucleus collisions.
Gravitational scattering in the ADD-model is considered at both sub- and transplanckian energies using a common formalism. By keeping a physical cut-off in the KK tower associated with virtual KK exchange, such as the cut-off implied from a finite brane width, troublesome divergences are removed from the calculations in both energy ranges. The scattering behavior depends on three different energy
We propose a new description of the jet quenching phenomenon observed in nuclear collisions at high energies in which coherent parton branching plays a central role. This picture is based on the appearance of a dynamically generated scale, the jet resolution scale, which controls the transverse resolution power of the medium to simultaneously propagating color probes. Since from the point of view
