Related papers: Nonperturbative \gamma^* p Interaction in the Diff…
The inclusive single and double differential cross-sections for neutral and charged current processes with four-momentum transfer squared Q^2 between 150 and 30,000 GeV2 and with Bjorken x between 0.0032 and 0.65 are measured in e^+ p…
We calculate the differential cross section for real photon electroproduction off spinless hadron which sevres as a main probe of the hadrons structure via the concept of generalized parton distributions. Compared to previously available…
In-medium interactions of a particle in a hot plasma are considered in the framework of thermal field theory. The formalism to calculate gauge invariant rates for photon and dilepton production from the medium is given. In the application…
The proton structure function in the diffraction region of small Bjorken-$x$ and $10 {\rm GeV}^2 \le Q^2 \le 100 {\rm GeV}^2$ behaves as $F_2 (x, Q^2) = F_2 (W^2) = f_0 \cdot (W^2)^{C_2}$, where $x = Q^2 / W^2$. The exponent $C_2$ of the…
The long standing mystery of smallness of diffractive dissociation of hadrons to large effective masses (the Pomeron-proton cross section is only 2 mb) witnesses that the gluonic clouds of valence quarks are so small (r_0=0.3fm) that soft…
In a framework for nonperturbative QCD calculation of high energy processes, the amplitudes for photo- and electroproduction of vector mesons are written as integrals of the overlap product of photon and vector meson wave functions,…
Results of a next-to-leading order calculation of the inclusive cross section for a photon and a heavy quark (charm or bottom), $p \bar p / pp \to \gamma +Q +X$, are presented. Pointlike photon subprocesses through ${\cal…
We demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive exclusive production of photons at large $Q^2$ at HERA, while the aligned jet model allows one to estimate the cross section for…
The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections…
Using the analytical expression for transverse momentum dependent (TMD) gluon density in a proton, a self-consistent simultaneous description of low $Q^2$ data on proton structure function $F_2(x,Q^2)$, reduced cross section for the…
The amplitude of diffractive $\rho$ (and open quark) leptoproduction on a polarized target is calculated in the leading log approximation of pQCD using the hadron-parton duality hypothesis. The spin-spin asymmetry is expressed in terms of…
Inclusive jet cross sections for events with a large rapidity gap with respect to the proton direction from the reaction $ep \rightarrow jet \; + \; X$ with quasi-real photons have been measured with the ZEUS detector. The cross sections…
Exclusive two-pion production near threshold in the collision of a highly virtual photon with a real one offers a new possibility to unravel the partonic content of hadrons. We explain the dynamics of this regime, i.e. the separation of the…
We provide a perspective on studies aimed at observing the transition between hadronic and quark-gluonic descriptions of reactions involving light nuclei. We begin by summarizing the results for relatively simple reactions such as the pion…
This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process $e p \to e' p \pi^{+} \pi^{-} $. The data were collected with the CLAS detector at Jefferson Laboratory.…
Diffractive photoproduction of rho, phi and J/psi was studied in the BFKL approach to hard colour singlet exchange. Differential cross sections, the energy dependence and spin density matrix elements were calculated and compared to data…
We investigate neutral pion electroproduction off protons in the framework of heavy baryon chiral perturbation theory. The chiral expansion of the S--wave multipoles $E_{0+}$ and $L_{0+}$ is carried out to three orders. There appear several…
Exclusive hadron production processes in photon-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes and skewed parton distributions. The determination of the…
In this paper we study the inelastic quarkonium photoproduction in coherent $pp/pPb/PbPb$ interactions. Considering the ultra relativistic hadrons as a source of photons, we estimate the total $ h_1 + h_2 \rightarrow h \otimes V + X$ ($V =…
The photoproduction of Drell-Yan lepton pairs at HERA is studied. We show that in the backward rapidity region the cross section is strongly sensitive to the small-$x$ behaviour of the quark distributions in the proton, and that with…