Related papers: Two-Photon Processes and Photon Structure
Development of concepts related to the photon and its high energy hadronic interaction is briefly reviewed. A photon considered as an ideal probe of hadron structure, paradoxically is also considered as an ideal target to test the…
We discuss the perturbatively calculable virtual photon structure functions. First we present the framework for analyzing the structure functions of the virtual photon and derive a first moment of $g_1^\gamma$ of the virtual photon. We then…
The term two--photon processes is used for the reactions in which some system of particles is produced in collision of two photons, either real or virtual. In the study of these processes our main goal was to suggest approach, allowing to…
Measurements sensitive to the structure of both real and virtual photons are presented and compared to theoretical models with various photon parton distribution functions (PDFs). Measurements for real photons show a tendency for the…
The concept of the structure of the photon is discussed and the progress in the measurement of various structure functions of the photon as well of parton distributions in the photon is shortly reviewed.
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…
We study the virtual photon structure functions from gauge/string duality. If the Bjorken variable x is not small, supergravity approximation becomes good in dual string theory. We calculate the virtual photon structure functions at large…
We point out that in processes involving the parton content of the photon the usual effective photon approximation should be modified. The reason is that the parton content of virtual photons is logarithmically suppressed compared to real…
The structure functions F_2 and F_1 of real photon at low virtualities are calculated in the framework of chiral perturbation theory (ChPT) in the zero and first order of ChPT. It is assumed that the virtuality of hard projectile photon Q^2…
In this talk I present a summary of some of the discussions at the conference on various topics in Photon physics, selected with a view to give a theorist's perspective, of the current status and future prospects, of the developments in the…
An overview of the current data and phenomenology on the structure of the photon and an outline of some opportunities available in the medium term future.
This review covers selected results from the LEP experiments on the structure of quasi-real and virtual photons. The topics discussed are the total hadronic cross-section for photon-photon scattering, hadron production, jet cross-sections,…
We discuss the structure functions and the parton distributions in the virtual photon target, both polarized and unpolarized, beyond the leading order in QCD. We study the factorization-scheme dependence of the parton distributions.
Structure of the space of photonic states is discussed in the context of a working hypothesis of existence of a preferred frame for photons. Two polarisation experiments are proposed to test the preferred frame scenario.
Interactions of virtual photons are analyzed in terms of photon structure. It is argued that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photons involved in hard collisions. The…
LEP offers an excellent opportunity to measure two photon processes over a large kinematical range and thus study the complex nature of the photon. This article reviews the experimental status of ``Two Photon Physics'' at LEP. The recent…
Jet production in $ep$ collisions is sensitive to the partonic structure of photon. The latest measurements of dijet production from the H1 experiment provide new results of the gluon density of real photons at low $x$ and, for the first…
Interactions of virtual photons are analyzed in terms of their parton distribution functions. It is shown that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photonds involved in hard…
We investigate the positivity constraints for the structure functions of both virtual and real photon. From the Cauchy-Schwarz inequality we derive three positivity conditions for the general virtual photon case, which reduce, in the real…
Present data on the partonic content of the photon from LEP, TRISTAN and HERA accelerators are reviewed and the essential aspects of the underlying ideas and methods are pointed out. Results of the unpolarized photon structure function F_2…