Related papers: Parton content of the real photon: astrophysical i…
In some cases it may be useful to know parton distributions in a photon gas. This may be relevant, e.g., for the analysis of interactions of high energy cosmic ray particles with the cosmic microwave background radiation. The latter can be…
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. This…
Properties of nucleon and $\Delta$ resonances are derived from a multichannel partial wave analysis. The statistical significance of pion and photo-induced inelastic reactions off protons are studied in a multichannel partial-wave analysis.
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 calculate the photon production cross section arising from the hard scattering of partons in nucleon-nucleon collisions by taking into account the intrinsic parton transverse momentum distribution and the next-to-leading-order…
The QCD treatment of the photon structure is recalled. Emphasis is given to the recently derived momentum sum rule, and to the proper choice of the factorization scheme and/or boundary conditions for the evolution equations beyond the…
The structure of the photon is studied in photon-photon collisions at LEP. New measurements have become available exploring the structure function F2g of the photon to the lowest values of x yet, where the hadronic component of the photon…
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…
At energies above the threshold for $W$ production the process $\nu \gamma \to l W^+$ is competive with $\nu \nu$ scattering at the same center of mass energies. In a cosmological setting, absorption of ultra high energy neutrinos by the…
Deepening our knowledge of the partonic content of nucleons and nuclei represents a central endeavour of modern high-energy and nuclear physics, with ramifications in related disciplines such as astroparticle physics. There are two main…
We discuss in detail the photon structure function beyond the leading logarithm approximation. Of special concern is the factorization scheme and the hadronic input; we show how to naturally absorb large terms due to the MSbar factorization…
Leading order parton distributions in the photon are extracted from the existing $F_2^\gamma$ measurements and the low-$x$ proton structure function. The latter is related to the photon structure function by assuming Gribov factorization to…
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…
The equivalent photon content of polarized and unpolarized nucleons (protons, neutrons), utilized in Weizs\"acker--Williams approximations, are presented. For this purpose a new expression for the elastic photon component of a polarized…
The QCD treatment of the parton structure of virtual photons is briefly recalled, and possible limitations and open questions are pointed out. Various models for these densities are compared, completed by a short discussion of the treatment…
I discuss the parton distributions in the photon and the constraints coming from the jet production in photoproduction and in photon-photon collisions.
$W^+ W^-$ production is one of the golden channels for testing the Standard Model as well for searches beyond the Standard Model. We discuss many new subleading processes for inclusive production of $W^+ W^-$ pairs generally not included in…
For photons that propagate through a gas of neutrinos with a non-zero chemical potential, the left-handed and right-handed polarization modes acquire different dispersion relations. This is due to the CP and CPT-odd terms induced by such a…
We introduce a general expression which enables the parton distribution, unintegrated over the parton transverse momentum, to be obtained from the conventional parton densities. We use the formalism to study the effects of the transverse…
Direct photon production in association with a heavy quark can serve as an excellent tool for the study of the heavy quark distributions. Currently it is believed that heavy quarks are produced radiatively inside the nucleon, and so there…