6,243 research outputs found
Parton distributions in the photon from and scattering
Leading order parton distributions in the photon are extracted from the
existing measurements and the low- proton structure function.
The latter is related to the photon structure function by assuming Gribov
factorization to hold at low . The resulting parton distributions in the
photon are found to be consistent with the Frankfurt-Gurvich sum rule for the
photon.Comment: 8 pages, including 4 figure
The Hadronic Final State at HERA
The hadronic final state in electron-proton collisions at HERA has provided a
rich testing ground for development of the theory of the strong force, QCD. In
this review, over 200 publications from the H1 and ZEUS Collaborations are
summarised. Short distance physics, the measurement of processes at high energy
scales, has provided rigorous tests of perturbative QCD and constrained the
structure of the proton as well as allowing precise measurements of the strong
coupling constant to be made. Non-perturbative or low energy processes have
also been investigated and results on hadronisation interpreted together with
those from other experiments. Searches for exotic QCD objects, such as
pentaquarks, glueballs and instantons have been performed. The subject of
diffraction has been re-invigorated through its precise measurement, such that
it can now be described by perturbative QCD. After discussion of HERA, the H1
and ZEUS detectors and the techniques used to reconstruct differing hadronic
final states, the above subject areas are elaborated. The major achievements
are then condensed further in a final section summarising what has been
learned.Comment: 60 pages, 65 figures, submitted to Reviews of Modern Physics. Updated
version includes comments to the text from journal referee
Global Parton Distributions for the LHC Run II
We review the next generation global PDF sets: NNPDF3.0, MMHT14 and CT14. We
describe the global datasets, particularly the new data from LHC Run 1, recent
developments in QCD theory and PDF methodology, improvements in combination and
delivery, and future prospects for parton determination at Run 2.Comment: 15 pages, 11 figures; talk given at La Thuile, 3rd March 2015;
updated reference
Management and Service-aware Networking Architectures (MANA) for Future Internet Position Paper: System Functions, Capabilities and Requirements
Future Internet (FI) research and development threads have recently been gaining momentum all over the world and as such the international race to create a new generation Internet is in full swing: GENI, Asia Future Internet, Future Internet Forum Korea, European Union Future Internet Assembly (FIA). This is a position paper identifying the research orientation with a time horizon of 10 years, together with the key challenges for the capabilities in the Management and Service-aware Networking Architectures (MANA) part of the Future Internet (FI) allowing for parallel and federated Internet(s)
Regge description of high energy pion pion total cross sections
We have recently presented a Regge description of pion-pion total cross
sections valid above 1.4 GeV, consistent with the few existing experiments,
factorization and crossing symmetry. In this note we show how it also describes
a further large data sample obtained from an analysis of experiments on
and .Comment: 3 pages. To appear in the proceedings of the MESON 2004 workshop,
Krakow, July 2004, to be published in Int. J. Mod. Phys.
Color coherent phenomena on nuclei and the QCD evolution equation
We review the phenomenon of color coherence in quantum chromodynamics (QCD),
its implications for hard and soft processes with nuclei, and its experimental
manifestations. The relation of factorization theorems in QCD with color
coherence phenomena in deep inelastic scattering (DIS) and color coherence
phenomena in hard exclusive processes is emphasized. Analyzing numerically the
QCD evolution equation for conventional and skewed parton densities in nuclei,
we study the onset of generalized color transparency and nuclear shadowing of
the sea quark and gluon distributions in nuclei as well as related phenomena.
Such novel results as the dependence of the effective coherence length on
and general trends of the QCD evolution are discussed. The limits of the
applicability of the QCD evolution equation at small Bjorken are estimated
by comparing the inelastic quark-antiquark- and two gluon-nucleon (nucleus)
cross sections, calculated within the DGLAP approximation, with the dynamical
boundaries, which follow from the unitarity of the matrix for purely QCD
interactions. We also demonstrate that principles of color coherence play an
important role in the processes of soft diffraction off nuclei.Comment: 58 pages, 19 figures, Revtex. Minor editor's changes, final version
published in J.Phys. G27 (2001) R23-6
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