251 research outputs found
Higher order QED corrections to deep inelastic scattering
We calculate the leptonic corrections for unpolarized
deeply inelastic ep scattering using mixed variables.Comment: 5 pages LaTeX, 1 style file, presented at RADCOR 2002, Kloster Banz,
Sept.8-13, 200
QCD Analysis of Polarized Deep Inelastic Scattering Data
A QCD analysis of the world data on inclusive polarized deep inelastic
scattering of leptons on nucleons is presented in leading and next-to-leading
order. New parameterizations are derived for the quark and gluon distributions
and the value of is determined. Emphasis is put on the
derivation of fully correlated error bands for these distributions which are
directly applicable to determine experimental errors of other polarized
observables. The impact of the variation of both the renormalization and
factorization scales on the value of is studied. Finally a
factorization-scheme invariant QCD analysis based on the observables
and is performed in next-to-leading
order, which is compared to the standard analysis.Comment: 6 pages LATEX, 4 aps style and other files, 3 eps-files, to appear in
the Proceedings of `QCD at Work', Martina Franca, June 200
Polarized Parton Densities
In this talk we summarize main results of a recent determination of the
polarized deeply inelastic parton distributions to NLO from the world data. In
the analysis the LO and NLO parton densities and their statistical
errors were derived and parameterized. The strong coupling constant
is determined Comparisons of the
low moments of the parton densities with recent lattice results are given. A
detailed error-analysis of the gluon density is performed.Comment: 3 pages LATEX, 1 style file, 1 eps file, to appear in the Proceedings
of PANIC '02, Osaka, Ocrober 200
Universal Higher Order Singlet QED Corrections to Unpolarized Lepton Scattering
We calculate the universal flavor-singlet radiative QED corrections to
unpolarized lepton scattering applicable to general differential scattering
cross sections, involving charged fermions or photons in initial or final
states. The radiators are derived to in analytic
form. Numerical illustrations are given.Comment: 31 pages, 3 figures, 1 style fil
Comparison of numerical solutions for Q^2 evolution equations
Q^2 evolution equations are important not only for describing hadron
reactions in accelerator experiments but also for investigating
ultrahigh-energy cosmic rays. The standard ones are called DGLAP evolution
equations, which are integrodifferential equations. There are methods for
solving the Q^2 evolution equations for parton-distribution and fragmentation
functions. Because the equations cannot be solved analytically, various methods
have been developed for the numerical solution. We compare brute-force,
Laguerre-polynomial, and Mellin-transformation methods particularly by focusing
on the numerical accuracy and computational efficiency. An efficient solution
could be used, for example, in the studies of a top-down scenario for the
ultrahigh-energy cosmic rays.Comment: 12 pages, LaTeX, 13 eps files, Journal of Computational Physics in
press, http://hs.phys.saga-u.ac.j
Target Mass Corrections to the Spin-dependent Structure Functions
The target mass corrections to the twist-2 contributions of the
spin-dependent structure functions are calculated using operator product
expansion in lowest order in QCD. The influence of such corrections to the
different relations between the structure functions is considered.Comment: 2 pages LATEX, contract number adde
Twist-2 Heavy Flavor Contributions to the Structure Function
The twist--2 heavy flavor contributions to the polarized structure function
are calculated. We show that this part of is related
to the heavy flavor contribution to by the Wandzura--Wilczek
relation to all orders in the strong coupling constant. Numerical results are
presented.Comment: 17 pages LATEX, 1 style files, 4 figure
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