K. Golec-Biernat

The High energy asymptotics of scattering processes in QCD

High energy scattering in the QCD parton model was recently shown to be a reaction-diffusion process, and thus to lie in the universality class of the stochastic Fisher-Kolmogorov-Petrovsky-Piscounov equation. We recall that the latter appears naturally in the context of the parton model. We provide a thorough numerical analysis of the mean field approximation, given in QCD by the Balitsky-Kovchegov equation. In the framework of a simple stochastic toy model that captures the relevant features of QCD, we discuss and illustrate the universal properties of such stochastic models. We investigate in particular the validity of the mean field approximation and how it is broken by fluctuations. We find that the mean field approximation is a good approximation in the initial stages of the evolution in rapidity.

Nonlinear equation for coherent gluon emission

A bstractMotivated by the regime of QCD explored nowadays at LHC, where both the total energy of collision and momenta transfers are high, we investigate evolution equations of high energy factorization. In order to study such effects like parton saturation in final states one is inevitably led to investigate how to combine physics of the BK and CCFM evolution equations. In this paper we obtain a new exclusive form of the BK equation which suggests a possible form of the nonlinear extension of the CCFM equation.

QCD analysis of deep inelastic diffractive scattering at HERA

Abstract The QCD analysis of deep inelastic diffractive scattering is performed assuming the dominance of the “soft” pomeron exchange and a simple, physically motivated parametrization of the parton distributions in a pomeron. Results of the analysis are compared with the recent data obtained by the H1 Collaboration at HERA. Both the LO and NLO approximations are considered and the theoretical predictions concerning the quantity R = F L D F T D for diffractive structure functions are presented.

Constraining the double gluon distribution by the single gluon distribution

Abstract We show how to consistently construct initial conditions for the QCD evolution equations for double parton distribution functions in the pure gluon case. We use to momentum sum rule for this purpose and a specific form of the known single gluon distribution function in the MSTW parameterization. The resulting double gluon distribution satisfies exactly the momentum sum rule and is parameter free. We also study numerically its evolution with a hard scale and show the approximate factorization into product of two single gluon distributions at small values of x , whereas at large values of x the factorization is always violated in agreement with the sum rule.

Heavy flavor production in DGLAP improved saturation model

The charm and beauty quark production in deep inelastic scattering at low values of the Bjorken variable x is considered in the DGLAP improved saturation model. After fitting parameters of the model to the structure function F_2, the heavy quark contributions Fc_2 and Fb_2 are predicted. A good description of the data is found. Predictions for the longitudinal structure function F_L and the diffractive structure function FD_2 are also presented.

Generalized Valon Model for Double Parton Distributions

We show how the double parton distributions may be obtained consistently from the many-body light-cone wave functions. We illustrate the method on the example of the pion with two Fock components. The procedure, by construction, satisfies the Gaunt–Stirling sum rules. The resulting single parton distributions of valence quarks and gluons are consistent with a phenomenological parametrization at a low scale.

Electroweak vector boson production at the LHC as a probe of mechanisms of diffraction

We show that the double diffractive electroweak vector boson production in the

Dipole model analysis of the newest diffractive deep inelastic scattering data

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On the use of the KMR unintegrated parton distribution functions

collisions at the LHC is an ideal probe of QCD based mechanisms of diffraction. Assuming the resolved Pomeron model with flavor symmetric parton distributions, the

Saturation model of DIS: an update

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