5,135 research outputs found
Polarized Structure Functions in QCD
We review the nucleon's polarized structure functions from the viewpoint of
gauge invariant, nonlocal light-cone operators in QCD. We discuss a systematic
treatment of the polarized structure functions and the corresponding parton
distribution functions. We also address a question of what information on the
structure of Nature will be obtained from the future polarized experiments.
From this point of view, we will discuss the W gamma production at RHIC
polarized experiment.Comment: 8 pages, 5 Postscript figures, Invited talk presented at the Workshop
on Lepton Scattering, Hadrons and QCD, Adelaide, March 26 -- April 6, 200
Spin Structure Function and Twist-3 Operators in QCD
We investigate the spin structure function in the framework
of the operator product expansion and the renormalization group. The twist-3
operators appearing in QCD are examined and their relations are studied. It is
noted that operators proportional to equation of motion appear in the operator
mixing through renormalization, which can be studied from the relevant Green's
functions. We also note that the coefficient functions can be properly fixed
after the choice of independent operators.Comment: LaTeX, 11 pages, KUCP-71; HUPD-941
Goto's generalized Kaehler stability theorem
In these notes we give a shortened and more direct proof of Goto's
generalized Kaehler stability theorem stating that if (J_1,J_2) is a
generalized kaehler structure for which J_2 is determined by a nowhere
vanishing closed form, then small deformations of J_1 can be coupled with small
deformations of J_2 so that the pair remains a generalized Kaehler structure.Comment: 9 pages, 5 figure
Twist-3 polarized structure functions
We review the nucleon's twist-3 polarized structure functions from the
viewpoint of gauge invariant, nonlocal light-cone operators in QCD. We discuss
a systematic treatment of the polarized structure functions and the
corresponding parton distribution functions. We emphasize unique features of
higher twist distributions, and the role of the QCD equations of motion to
derive their anomalous dimensions for Q^2-evolution.Comment: 6 pages LaTeX, talk given at the QCD 99 Euroconference, Montpellier,
July 7-13, 199
Conifold geometries, topological strings and multi-matrix models
We study open B-model representing D-branes on 2-cycles of local Calabi--Yau
geometries. To this end we work out a reduction technique linking D-branes
partition functions and multi-matrix models in the case of conifold geometries
so that the matrix potential is related to the complex moduli of the conifold.
We study the geometric engineering of the multi-matrix models and focus on
two-matrix models with bilinear couplings. We show how to solve this models in
an exact way, without resorting to the customary saddle point/large N
approximation. The method consists of solving the quantum equations of motion
and using the flow equations of the underlying integrable hierarchy to derive
explicit expressions for correlators. Finally we show how to incorporate in
this formalism the description of several group of D-branes wrapped around
different cycles.Comment: 35 pages, 5.3 and 6 revise
OPE analysis for polarized deep inelastic scattering
We present an explicit OPE analysis for the first moment of up to order
. This result allows to calculate power corrections to the Bjorken and
Ellis--Jaffe sum rules.Comment: 10 pages, minor modifications, revised version for the journa
Polarized Parton Distributions in the Photon and Factorization Scheme Dependence
Spin-dependent parton distributions in the polarized virtual photon are
investigated in QCD up to the next-to-leading order (NLO). In the case
, where () is the mass squared of the
probe (target) photon, parton distributions can be predicted completely up to
the NLO, but they are factorization-scheme-dependent. Parton distributions are
analyzed in four different factorization schemes and their scheme dependence
are discussed. Particular attentions are paid to the axial anomaly effect on
the first moments of quark parton distributions, and also to the large-
behaviors of the parton distributions. Gluon distribution in the virtual photon
is found to be factorization-scheme independent up to the NLO.Comment: 15 pages, LaTeX, 3 postscript figures; one page shortened, refined
arguments, no change in results and conclusion
More on the Burkhardt-Cottingham Sum Rule in QCD
The QCD higher order effects to the polarized structure function are reanalyzed for massive quarks in the context of the operator product
expansion. We confirm that the lowest moment of which
corresponds to the Burkhardt-Cottingham sum rule does {\sl not} suffer from
radiative corrections in perturbative QCD.Comment: LaTeX, 9 pages, 1 figure appended after \end{document} as an
uu-encoded and compressed .ps file, KUCP-70;HUPD-9410;YNU-HEPTh-94-10
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