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Henri Kowalski

Publications and source records attributed to Henri Kowalski.

6 recordsLinked to original sources
arXiv2019

Investigation of High Energy Behaviour of HERA Data

We analyse the high precision HERA $F_2$ data in the low-$x$ regions, $x<0,01$ and the very-low-$x$, $x<0.001$, regions using $λ$-Fits. $λ$ is a measure of the rate of rise of $F_2$ defined by $F_2 \propto (1/x)^λ$. We show that $λ$ determined in these two regions, at various $Q^2$ values, is systematically smaller in the very-low-$x$ region as compared to the low-$x$ region. We discuss some possible physical interpretations of this effect.

hep-ph↗
arXiv2019

Dipole model analysis of high precision HERA data

We analyse, within a dipole model, the inclusive DIS cross section data, obtained from the combination of the H1 and ZEUS HERA measurements. We show that these high precision data are very well described within the dipole model framework, which is complemented with a valence quark structure functions. We discuss the properties of the gluon density obtained in this way.

hep-ph↗
arXiv2017

Dipole model analysis of highest precision HERA data, including very low $Q^2$'s

We analyse, within a dipole model, the final, inclusive HERA DIS cross section data in the low $x$ region, using fully correlated errors. We show, that these highest precision data are very well described within the dipole model framework starting from $Q^2$ values of 3.5 GeV$^2$ to the highest values of $Q^2 =$ 250 GeV$^2$.

hep-ph↗
arXiv2014

The Green Function for the BFKL Pomeron and the Transition to DGLAP Evolution

We consider the (process-independent) Green function for the BFKL equation in the next-to-leading order approximation, with running coupling, and explain how, within the semi-classical approximation, it is related to Green function of the Airy equation. The unique Green function is obtained from a combination of its required ultraviolet behaviour compatible with asymptotic freedom and an infrared limit phase imposed by the non-perturbative sector of QCD. We show that at sufficiently large gluon transverse momenta the corresponding gluon density matches that of the DGLAP analysis, whereas for relatively small values of the gluon transverse momentum the gluon distribution is sensitive to the Regge poles, whose positions are determined both by the non-pertubative QCD dynamics and physics at large transverse momenta.

hep-ph↗
arXiv2003

An Impact Parameter Dipole Saturation Model

We develop a dipole model for HERA DIS data which incorporates the impact parameter distribution of the proton. The model describes the inclusive total $γ^*p$ cross-sections as well as the diffractive $J/ψ$ differential cross-sections. We compare the model with previous approaches and show that the $t$-distributions are sensitive to saturation phenomena. We estimate the boundary of the saturation region and show that it dominates the data in the low-$Q^2$ region where the total $γ^*p$ cross-section exhibits the same universal rise as hadronic cross-sections. The model is then extended to nuclei and shows good agreement with the nuclear shadowing data at small-$x$. Finally, we estimate the saturation scale in nuclei.

hep-ph↗