Related papers: Interpreting virtual photon interactions in terms …
The problem of dealing with the resolved photon contribution to $P^2$-integrated $ep$ cross sections is discussed. Suitable approximations have to be found, since no parametrization of the photon structure function in the full range of…
Recent results on structure functions and parton distribution functions at HERA are presented. Results on the measurements of the structure functions F2, FL and F3 will be covered, as well as the results of the most recent QCD fits to…
It is shown that the hadronic dissociation of space-like $(Q^2>0)$ photons can be directly probed by performing measurements in the fragmentation region of transversely polarized and unpolarized proton beams at the electron-proton collider…
Experimental results obtained with the HERA collider and recent progress in their theoretical interpretation are reviewed. After a short introduction to HERA physics, deep inelastic scattering and photoproduction are discussed as (virtual)…
A significant fraction of pp collisions at the LHC will involve (quasi-real) photon interactions occurring at energies well beyond the electroweak energy scale. Hence, the LHC can to some extend be considered as a high-energy photon-photon…
The recent F$_2$ measurements at HERA are discussed in the framework of virtual photon--proton cross section. The energy behaviour of the cross section is studied for different $Q^2$ values, ranging from 0 to 1000 GeV$^2$ for center of mass…
We study various conceivable photoproduction reactions in a polarized ep collider mode of HERA with respect to their sensitivity to the proton's polarized gluon distribution. A special emphasis is put on the `resolved' part of the cross…
At HERA, the electron-proton collider at DESY, Hamburg, the large flux of almost on-shell photons accompanying the lepton beam is being used to shed new light on the structure of the photon. Recent results are reviewed and discussed, with…
We review next-to-leading order calculations of one- and two-jet production in ep collisions at HERA for photon virtualities in the range 1<Q^2<100 GeV^2. Soft and collinear singularities are extracted using the phase space slicing method.…
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…
We determine diffractive parton distributions of the proton from DGLAP based fits to HERA data including the twist--4 contribution from longitudinal polarized virtual photons, which is known to be important in the region of large beta. The…
The shapes of invariant differential cross section for charged hadron production as function of hadron's transverse momentum and rapidity in ep collisions at HERA machine are considered. The particle spectra shapes observed in pp and…
Standard parton distribution functions contain neither information on the correlations between partons nor on their transverse motion, then a vital knowledge about the three dimensional structure of the nucleon is lost. Hard exclusive…
The sensitivity of the Deep Inelastic Compton (DIC) scattering at HERA to the structure of the virtual photon is discussed. It is demonstrated that the gluonic content of the virtual photon can be pinned down by measuring the photons with…
The triple-differential dijet cross-section, d^3 sigma_{ep}/dQ2 dE_t2 dxgjets, is measured with the H1 detector at HERA as a function of the photon virtuality Q^2, the fraction of the photon's momentum carried by the parton entering the…
We review the present level of knowledge of the hadronic structure of the photon, as revealed in interactions involving quarks and gluons ``in" the photon. The concept of photon structure functions is introduced in the description of…
It is shown that by assuming Gribov factorization to hold at low $x$ one obtains a simple relation between the structure function of the proton and that of the photon. By interpreting an observed structure in deep inelastic scattering (DIS)…
The energy dependence of cross sections is discussed as a way to learn about the dynamics of photon induced interactions at HERA. The question of determining the scale of exclusive electroproduction of vector mesons is addressed.
The hadronic interactions of the photon are studied in terms of new measurements of the total hadronic cross section and di-jet production in photon-photon collisions at LEP2.
Twist-2 components of the real and virtual photon distribution amplitudes are evaluated in several chiral quark models. The results, obtained at the quark model scale, are then evolved to higher scales, probed in experiments or in lattice…