A. B. Kaidalov

Comment on the heavy→light form factors

Abstract We propose a simple parameterization for the form factors in heavy to light decays, which satisfies the heavy quark scaling laws and avoids introducing the explicit “dipole” form. The illustration is provided with the set of lattice data for B → π semileptonic decay. The resulting shape of the form factor also agrees with the QCD sum rule predictions.

Structure functions and low x physics

Abstract In the framework of conventional Regge theory we present a common description of total photon-proton cross-section and proton structure functions in the region 0≤Q2≤5 GeV2. Using it as an initial condition in the perturbative QCD evolution equation, we describe structure functions at any Q2 and x-including the small x region explored at HERA.

Jψ and ψ′ suppression in heavy ion collisions

Abstract We study the combined effect of nuclear absorption and final state interaction with co-moving hadrons on the J ψ and ψ′ suppression in proton-nucleus and nucleus-nucleus collisions. We obtain a reasonable description of the PbPb data using theoretically meaningful values of the cross-sections involved and without introducing any discontinuity in the J ψ or ψ′ survival probabilities. However, the description of both pA and SU data is significantly worse than the one obtained with nuclear absorption alone.

Diffractive dissociation in deep inelastic scattering at HERA

Abstract The diffraction dissociation of virtual photons is considered in the framework of conventional Regge theory. It is shown that the recent HERA data on large rapidity gap events can be successfully described in terms of the pomeron structure function. Using Regge factorization, the latter can be related to the deuteron structure function. The parameters which relate these two structure functions are determined from soft hadronic diffraction data. The size of the shadowing corrections at low x and large Q 2 is also obtained.

Nuclear structure functions at small x from inelastic shadowing and diffraction

Abstract.Nuclear structure functions at small x and small or moderate Q2 are studied using the relation with diffraction on nucleons which arises from Gribovs reggeon calculus. A reasonable description of the experimental data is obtained with no fitted parameters. A comparison with other models and predictions for future lepton-ion colliders are provided. Consequences for the reduction of multiplicities in nucleus-nucleus collisions at energies of RHIC and LHC are examined.

Gluon shadowing in the Glauber–Gribov model at HERA

Abstract We calculate shadowing using new data on the gluon density of the pomeron recently measured with high precision at HERA. The calculations are made in a Glauber–Gribov framework and pomeron tree-diagrams are summed up within a unitarity-conserving procedure. The total cross section of γ ∗ A interaction is then found in a parameter-free description, employing gluon diffractive and inclusive distribution functions as input. A strong shadowing effect is obtained, in a good agreement with several other models. Impact parameter dependence of gluon shadowing is also presented.

Deep inelastic scattering data and the problem of saturation in small x physics

We investigate the role of unitarization effects in virtual photon-proton (\gamma^*p) interactions at small x. The q\bar{q}-fluctuation of the initial photon is separated into a small distance and a large distance component and a model for the unitarization of each component is proposed. The Born approximation for the small size component is calculated using QCD perturbation theory. Reggeon diagram technique is used in order to obtain a self-consistent scheme for both total \gamma^*p cross section and diffractive production. The model gives a good description of HERA data in the small-x region, with a single Pomeron of intercept 1.2.

Production of vector mesons by real and virtual photons at high energies

Abstract A model based on Reggeon field theory is used for the description of the photo- and electroproduction of vector mesons (ϱ0, ω, φ, J ψ ) on the proton. Its main feature is the dependence of the Pomeron intercept on the virtuality of the photon. The few parameters of the model were determined by fitting the total cross sections for real and virtual photons on the proton. This allows a parameter-free description of the energy dependence of vector meson production. Very good agreement with the existing high energy data is obtained.

Nuclear shadowing in Glauber–Gribov theory with Q 2 -evolution

We consider deep inelastic scattering off nuclei in the Regge limit within the Glauber–Gribov model. Using unitarized parton distribution functions for the proton, we find sizeable shadowing effects on the nuclear total and longitudinal structure functions,

Coherent J/ψ production - a novel feature at LHC?

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