4,378 research outputs found

    Polarized Structure Functions in QCD

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    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 g2g_2 and Twist-3 Operators in QCD

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    We investigate the spin structure function g2(x,Q2)g_2 (x, Q^2 ) 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

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    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

    Conifold geometries, topological strings and multi-matrix models

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    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

    Transverse double-spin asymmetries for small QTQ_T Drell-Yan pair production in pppp and ppˉp\bar{p} collisions

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    We discuss transverse double-spin asymmetries for dimuon production at small transverse-momentum QTQ_T in pppp and ppˉp\bar{p} collisions. All order resummation of large logarithms relevant in small QTQ_T region is performed at next-to-leading logarithmic (NLL) accuracy, and asymmetries at RHIC, J-PARC and GSI are calculated.Comment: 4 pages, 2 figures, Talk given at DIS06, April 20-24, 2006, Tsukuba, Japa

    Reduction of Vaisman structures in complex and quaternionic geometry

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    We consider locally conformal Kaehler geometry as an equivariant (homothetic) Kaehler geometry: a locally conformal Kaehler manifold is, up to equivalence, a pair (K,\Gamma) where K is a Kaehler manifold and \Gamma a discrete Lie group of biholomorphic homotheties acting freely and properly discontinuously. We define a new invariant of a locally conformal Kaehler manifold (K,\Gamma) as the rank of a natural quotient of \Gamma, and prove its invariance under reduction. This equivariant point of view leads to a proof that locally conformal Kaehler reduction of compact Vaisman manifolds produces Vaisman manifolds and is equivalent to a Sasakian reduction. Moreover we define locally conformal hyperkaehler reduction as an equivariant version of hyperkaehler reduction and in the compact case we show its equivalence with 3-Sasakian reduction. Finally we show that locally conformal hyperkaehler reduction induces hyperkaehler with torsion (HKT) reduction of the associated HKT structure and the two reductions are compatible, even though not every HKT reduction comes from a locally conformal hyperkaehler reduction.Comment: 29 pages; Section 4 changed (and accordingly the Introduction); Remark 8.2 added; References update
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