László Jenkovszky

From Regge behavior to DGLAP evolution

Abstract. 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

Where is the black disc limit

Q^2

A Deeply Virtual Compton Scattering Amplitude

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Unitarity, (anti)shadowing, and black-disk limit

By using realistic models for elastic hadron scattering we demonstrate that at present accelerator energies the s-channel unitarity bound is safe, not to be reached until 10 5 GeV, while the black disc limit is saturated around 1 TeV. It will be followed by a larger transparency of the scattered particles near the center.

How fast do small x structure functions rise? A comparative analysis

Abstract A factorized Regge-pole model for deeply virtual Compton scattering is suggested. The use of an effective logarithmic Regge-pomeron trajectory provides for the description of both “soft” (small | t | ) and “hard” (large | t | ) dynamics. The model contains explicitly the photoproduction and the DIS limits and fits the existing HERA data on deeply virtual Compton scattering.

J/ψphotoproduction at DESY HERA

By using realistic models for elastic hadron scattering, we demonstrate that, at current accelerator energies, the s-channel unitarity bound is safe and is not to be reached until 105 GeV, while the black-disk limit is saturated around 6 TeV. It will be followed by a larger transparency of the scattered particles near the center.

Small x extrapolation of structure functions and the Pomeron

Abstract We parametrize the small x , singlet component of the proton structure function F 2 by powers and logarithms of 1/ x for discrete values of Q 2 between 0.2 and 2000 GeV 2 , and compare these parametrizations by applying the criterion of minimal χ 2 . The obtained values of the fitted parameters may be used to study the evolution of F 2 in Q 2 and/or in discriminating between dynamical models. A slowing-down in the increase of F 2 towards highest available values of Q 2 is revealed. The effect is quantified in terms of the derivative d ln F 2 ( x , Q 2 )/ d ln(1/ x ).

Ultrahigh-energy neutrino nucleon interactions

We revise and update an earlier model for

Q2 evolution of F2 (x, Q2) at small x from NMC to the HERA data

J/\psi

Vector meson production in ultra-peripheral collisions at the LHC

photoproduction based on a dipole Pomeron exchange. We show that the H1 and ZEUS experimental data reported recently can be well fitted by a soft Pomeron alone.