Calculation of hyperfine splitting in mesons using configuration interaction approach

The spin - spin mass splitting of light, heavy and mixed mesons are described within a good accuracy in the potential model with screened potential. We conclude that the long - distance part of the potential cannot be pure scalar and that a vector - scalar mixture is favoured. With the same parameters which gives correct average mass spectrum excellent spin - spin splittings of heavy quarkonia is obtained. The results are obtained by going beyond usually used perturbation method, namely using configuration interaction approach.Comment: 8 pages, LaTe

The soft and the hard pomerons: elastic scattering and unitarisation

The hard pomeron component needed to reproduce small-x data seems to be present in elastic scattering at moderate energy. If this is the case, it is likely that the total cross section at the LHC will be appreciably larger than previously expected.Comment: Talk given at 12th International Conference on Elastic and Diffractive Scattering: Forward Physics and QCD, Hamburg, DESY, Germany, 21-25 May 200

Hard pomeron contribution to forward elastic scattering

The introduction of a hard singularity in fits to total cross sections and to the ratio of real to imaginary parts enables to reproduce perfectly the data for sqrt(s)< 100 GeV using only simple-pole parametrisations, both for the soft and for the hard pomerons.Comment: Contribution to the proceedings of the XIth International Conference on Elastic and Diffractive Scattering, Chateau de Blois, France, May 15 - 20, 2005. Needs Blois.sty (provided

Turing Instability in a Boundary-fed System

The formation of localized structures in the chlorine dioxide-idodine-malonic acid (CDIMA) reaction-diffusion system is investigated numerically using a realistic model of this system. We analyze the one-dimensional patterns formed along the gradients imposed by boundary feeds, and study their linear stability to symmetry-breaking perturbations (Turing instability) in the plane transverse to these gradients. We establish that an often-invoked simple local linear analysis which neglects longitudinal diffusion is inappropriate for predicting the linear stability of these patterns. Using a fully nonuniform analysis, we investigate the structure of the patterns formed along the gradients and their stability to transverse Turing pattern formation as a function of the values of two control parameters: the malonic acid feed concentration and the size of the reactor in the dimension along the gradients. The results from this investigation are compared with existing experiments.Comment: 41 pages, 18 figures, to be published in Physical Review

From Regge Behavior to DGLAP Evolution

We study the interface between Regge behavior and DGLAP evolution in a non-perturbative model for the nucleon structure function based on a multipole pomeron exchange. This model provides the input for a subsequent DGLAP evolution that we calculate numerically. The soft input and its evolution give a good fit to the experimental data in the whole available range of x and Q^2.Comment: 7 pages, LaTeX, 4 figures. Text improved and reduced, figures modified, references updated. To be published in Eur. Phys. J. C in the present for