Related papers: Probing the Photon Structure Function in Photoprod…
New structure function measurements from fixed target experiments and especially HERA are reviewed. The extraction of parton distributions from these measurements is discussed with special emphasis on systematic problems. Finally the…
We study photoproduction of jets and heavy flavors in a polarized collider mode of HERA at $\sqrt{S}= 298$ GeV. We examine the sensitivity of the cross sections and their asymmetries to the proton's polarized gluon distribution and to the…
A study is presented of a possible future measurement of the longitudinal structure function $F_{L}(x,Q^{2})$ with different proton beam energies at HERA.
Present data on the partonic content of the photon are reviewed. The results on the unpolarized structure functions from DIS experiments and on large pt jet production processes in gamma-gamma and gamma-p collisions are discussed for both…
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…
A measurement is presented, using data taken with the H1 detector at HERA, of the contribution of diffractive interactions to deep-inelastic electron-proton scattering. The diffractive contribution to the proton structure function is…
The cross section for photoproduction of an isolated prompt photon in association with a jet is studied in Next-to-Leading Order. The kinematics are those appropriate for the DESY $ep$ collider HERA. The effects on the cross section of…
The present status of the measurements of hadronic structure functions of the photon, investigated in deep inelastic electron-photon scattering at LEP, is presented. This article covers the hadronic structure function F_2^gamma of…
The latest results on the structure of the proton and the photon as seen at HERA are reviewed while discussing the question posed in the title of the talk.
We study the cross section for dijet production via direct photons, as seen at the HERA collider. Rather than assuming the standard factorisation formula for the cross section (where the incoming partons are assumed to be on-shell), we use…
The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to…
The photon parton distribution function (PDF) of the proton is crucial for precise comparisons of LHC cross sections with theoretical predictions. However, it was previously affected by very large uncertainties of around ${\cal O}(100\%)$…
We suggest a method of determination of the pion structure function down to x \simeq 10^{-4} based on semi-exclusive deep inelastic scattering off protons. The idea is to exploit the nonperturbative \pi N$ and \pi\Delta Fock components of…
The structure of real and virtual photons has been studied in electron-proton scattering processes producing di-jet events at HERA by the H1 and ZEUS collaborations. Data have been compared to next-to-leading order QCD calculations and to…
Recently determined next-to-leading order sets of polarized parton distributions are used to study large-p_T $\vec{p}\vec{p}\rightarrow \gamma+X$ at $\sqrt{s}=38, 100 and 500 GeV$. Certain conversion terms, necessary to use the above sets,…
New data, especially HERA measurements of the proton structure function at small $x$, allow the opportunity to improve our knowledge of the gluon and quark distribution functions. We perform a global analysis which incorporates these new…
I investigate what a direct measurement of the longitudinal structure function F_L(x,Q^2) could teach us about the structure of the proton and the best way in which to use perturbative QCD for structure functions. I assume HERA running at a…
The experimental and phenomenological status of high energy photoproduction is reviewed. Topics covered include the structure of the photon, production of jets, heavy flavours and prompt photons, rapidity gaps, energy flow and underlying…
Prompt photon production is highly sensitive to the distribution of quarks and gluons in free protons and nuclei and an important baseline for phenomenological studies of the properties of the quark-gluon plasma. In this paper, we present a…
Heavy quarks are copiously produced in two-photon collisions at $e^+e^-$ colliders. The theoretical predictions including QCD radiative corrections are compared to recent experimental data on $\gamma\gamma$ production of charm quarks at…