7,176 research outputs found

    Implications of Hadron Collider Observables on Parton Distribution Function Uncertainties

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    Standard parton distribution function sets do not have rigorously quantified uncertainties. In recent years it has become apparent that these uncertainties play an important role in the interpretation of hadron collider data. In this paper, using the framework of statistical inference, we illustrate a technique that can be used to efficiently propagate the uncertainties to new observables, assess the compatibility of new data with an initial fit, and, in case the compatibility is good, include the new data in the fit.Comment: 22 pages, 5 figure

    Structure Functions in Deep Inelastic Lepton-Nucleon Scattering

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    Latest results on structure functions, as available at the Lepton-Photon Symposium 1999, are presented. This report focusses on three experimental areas: new structure function measurements, in particular from HERA at low x and high Q2; results on light and heavy flavour densities; determinations of the gluon distribution and of alpha_s. As the talk was delivered at a historic moment and place, a few remarks were added recalling the exciting past and looking into the promising future of deep inelastic scattering.Comment: 27 pages, latex, 15 figures, Talk at Lepton-Photon Symposium, Stanford, August 199

    Small x Behavior of Parton Distributions from the Observed Froissart Energy Dependence of the Deep Inelastic Scattering Cross Section

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    We fit the reduced cross section for deep-inelastic electron scattering data to a three parameter ln^2 s fit, A + beta ln^2 (s/s_0), where s= [Q^2/x] (1-x) + m^2, and Q^2 is the virtuality of the exchanged photon. Over a wide range in Q^2 (0.11 < Q^2 < 1200 GeV^2) all of the fits satisfy the logarithmic energy dependence of the Froissart bound. We can use these results to extrapolate to very large energies and hence to very small values of Bjorken x -- well beyond the range accessible experimentally. As Q^2 --> infinity, the structure function F_2^p(x, Q^2) exhibits Bjorken scaling, within experimental errors. We obtain new constraints on the behavior of quark and antiquark distribution functions at small x.Comment: 10 pages, 2 figure

    Cascading Quivers from Decaying D-branes

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    We use an argument analogous to that of Kachru, Pearson and Verlinde to argue that cascades in L^{a,b,c} quiver gauge theories always preserve the form of the quiver, and that all gauge groups drop at each step by the number M of fractional branes. In particular, we demonstrate that an NS5-brane that sweeps out the S^3 of the base of L^{a,b,c} destroys M D3-branes.Comment: 11 pages, 1 figure; v2: references adde

    On QCD Q2Q^2-evolution of Deuteron Structure Function F2D(xD,Q2)F_2^D(x_D,Q^2) for xD>1x_D>1

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    The deep-inelastic deuteron structure function (SF) F2D(xD,Q2)F_2^D(x_D,Q^2) in the covariant approach in light-cone variables is considered. The xDx_D and Q2Q^2-dependences of SF are calculated. The QCD analysis of generated data both for non-cumulative xD1x_D1 ranges was performed. It was shown that Q2Q^2-evolution of SF is valid for ranges 0.275<xD<0.850.275<x_D<0.85 and 1.1<xD<1.41.1<x_D<1.4 for the same value of QCD scale parameter Λ{\Lambda}. It was found the xDx_D-dependence of SF for the ranges is essentially different.Comment: LaTeX, 10 pages, 2 Postscript figure

    Cumulative structure function in terms of nucleonic wave function of the nucleus

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    The structure function of the nucleus in the cumulative region x>1x>1 is studied in terms of nucleon degrees of freedom. At high Q2Q^2 the resulting expressions are presented as a sum of contributions from few-nucleon correlations. Two-nucleon correlations are studied in some detail. Spin variables are averaged out. In the region 1<x<21<x<2 the structure functions are calculated for the relativistic interaction proposed by F.Gross {\it et al}. They are found to fall with xx faster than the exponential. For Carbon at x=1.05x=1.05, where the method is not rigorously applicable, they turn out to be rougly twice larger than the experimental data.Comment: text and 2 figures in LaTex, 7 figures in P

    On the pulsating strings in AdS_5 x T^{1,1}

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    We study the class of pulsating strings in AdS_5 x T^{1,1}. Using a generalized ansatz for pulsating string configurations we find new solutions of this class. Further we semiclassically quantize the theory and obtain the first correction to the energy. The latter, due to AdS/CFT correspondence, is supposed to give the anomalous dimensions of operators in the dual N=1 superconformal gauge field theory.Comment: 12 pages, improvements made, references adde

    Dual giant gravitons in AdSm_m Ă—\times Yn^n (Sasaki-Einstein)

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    We consider BPS motion of dual giant gravitons on AdS5Ă—Y5S_5\times Y^5 where Y5Y^5 represents a five-dimensional Sasaki-Einstein manifold. We find that the phase space for the BPS dual giant gravitons is symplectically isomorphic to the Calabi-Yau cone over Y5Y^5, with the K\"{a}hler form identified with the symplectic form. The quantization of the dual giants therefore coincides with the K\"{a}hler quantization of the cone which leads to an explicit correspondence between holomorphic wavefunctions of dual giants and gauge-invariant operators of the boundary theory. We extend the discussion to dual giants in AdS4Ă—Y7AdS_4 \times Y^7 where Y7Y^7 is a seven-dimensional Sasaki-Einstein manifold; for special motions the phase space of the dual giants is symplectically isomorphic to the eight-dimensional Calabi-Yau cone.Comment: 14 pages. (v2) typo's corrected; factors of AdS radius reinstated for clarity; remarks about dual giant wavefunctions in T^{1,1} expanded and put in a new subsectio

    New parton distributions from large-x and low-Q^2 data

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    We report results of a new global next-to-leading order fit of parton distribution functions in which cuts on W and Q are relaxed, thereby including more data at high values of x. Effects of target mass corrections (TMCs), higher twist contributions, and nuclear corrections for deuterium data are significant in the large-x region. The leading twist parton distributions are found to be stable to TMC model variations as long as higher twist contributions are also included. The behavior of the d quark as x-->1 is particularly sensitive to the deuterium corrections, and using realistic nuclear smearing models the d-quark distribution at large x is found to be softer than in previous fits performed with more restrictive cuts.Comment: 31 pages, 8 figures. Minor corrections. References added. To appear in Phys.Rev.

    Protein kinase CK2 is widely expressed in follicular, Burkitt and diffuse large B-cell lymphomas and propels malignant B-cell growth.

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    Serine-threonine kinase CK2 is highly expressed and pivotal for survival and proliferation in multiple myeloma, chronic lymphocytic leukemia and mantle cell lymphoma. Here, we investigated the expression of \u3b1 catalytic and \u3b2 regulatory CK2 subunits by immunohistochemistry in 57 follicular (FL), 18 Burkitt (BL), 52 diffuse large B-cell (DLBCL) non-Hodgkin lymphomas (NHL) and in normal reactive follicles. In silico evaluation of available Gene Expression Profile (GEP) data sets from patients and Western blot (WB) analysis in NHL cell-lines were also performed. Moreover, the novel, clinical-grade, ATP-competitive CK2-inhibitor CX-4945 (Silmitasertib) was assayed on lymphoma cells. CK2 was detected in 98.4% of cases with a trend towards a stronger CK2\u3b1 immunostain in BL compared to FL and DLBCL. No significant differences were observed between Germinal Center B (GCB) and non-GCB DLBCL types. GEP data and WB confirmed elevated CK2 mRNA and protein levels as well as active phosphorylation of specific targets in NHL cells. CX-4945 caused a dose-dependent growth-arresting effect on GCB, non-GCB DLBCL and BL cell-lines and it efficiently shut off phosphorylation of NF-\u3baB RelA and CDC37 on CK2 target sites. Thus, CK2 is highly expressed and could represent a suitable therapeutic target in BL, FL and DLBCL NHL
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