1,222 research outputs found

    Cooperative Marketing of Animal Health Products

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    This report uses eight case studies to identify elements of successful cooperative programs for retailing over-the-counter animal health products (AHP). It provides practical information on AHP marketing strategies and methods for cooperative retailers, planners, and researchers. All participating cooperatives except one provided information for fiscal years ending during calendar year 1986. The exception was for 1987. Information. about five AHP suppliers and their marketing programs is included to enhance understanding of retailer programs.Cooperative, advertising, animal health products, centralized, federated, local, margin, marketing, over-the-counter, Agribusiness, Livestock Production/Industries,

    Threshold Resummation for W-Boson Production at RHIC

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    We study the resummation of large logarithmic perturbative corrections to the partonic cross sections relevant for the process pp -> W^+- X at the BNL Relativistic Heavy Ion Collider (RHIC). At RHIC, polarized protons are available, and spin asymmetries for this process will be used for precise measurements of the up and down quark and anti-quark distributions in the proton. The corrections arise near the threshold for the partonic reaction and are associated with soft-gluon emission. We perform the resummation to next-to-leading logarithmic accuracy, for the rapidity-differential cross section. We find that resummation leads to relatively moderate effects on the cross sections and spin asymmetries.Comment: 25 pages, 15 figures as eps files. One reference added and typo correcte

    Soffer's inequality and the transversely polarized Drell-Yan process at next-to-leading order

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    We check numerically if Soffer's inequality for quark distributions is preserved by next-to-leading order QCD evolution. Assuming that the inequality is saturated at a low hadronic scale we estimate the maximal transverse double spin asymmetry for Drell-Yan muon pair production to next-to-leading order accuracy.Comment: 20 Pages, LaTeX, 7 figures as eps file

    Transverse Double-Spin Asymmetries for Muon Pair Production in pp-Collisions

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    We calculate the rapidity dependence of the transverse double-spin asymmetry for the Drell-Yan process to next-to-leading order in the strong coupling. Input transversity distributions are obtained by saturating the Soffer inequality at a low hadronic mass scale. Results for the polarized BNL-RHIC proton-proton collider and the proposed HERA-N fixed-target experiment are presented, and the influence of the limited muon acceptance of the detectors on measurements of the asymmetry is studied in detail.Comment: 7 pages including 5 figures; significantly shortened, to be published in Phys. Rev.

    Low-mass lepton pair production at large transverse momentum

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    We study the transverse momentum distribution of low-mass lepton pairs produced in hadronic scattering, using the perturbative QCD factorization approach. We argue that the distribution at large transverse momentum, QTQQ_T \gg Q, with the pair's invariant mass QQ as low as QΛQCDQ \sim \Lambda_{\mathrm{QCD}}, can be systematically factorized into universal parton-to-lepton pair fragmentation functions, parton distributions, and perturbatively calculable partonic hard parts evaluated at a short distance scale O(1/QT)\sim {\cal O}(1/Q_T). We introduce a model for the input lepton pair fragmentation functions at a scale μ01\mu_0\sim 1 GeV, which are then evolved perturbatively to scales relevant at RHIC. Using the evolved fragmentation functions, we calculate the transverse momentum distributions in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions at RHIC. We also discuss the sensitivity of the transverse momentum distribution of low-mass lepton pairs to the gluon distribution.Comment: 16 pages, 11 figures, revised version to appear in Phys. Rev.

    Polarized semi-inclusive electroweak structure functions at next-to-leading-order

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    We present a next-to-leading order (NLO) computation of the full set of polarized and unpolarized electroweak semi-inclusive DIS (SIDIS) structure functions, whose knowledge is crucial for a precise extraction of polarized parton distributions. We focus on the phenomenology of the polarized structure functions for the kinematical conditions that could be reached in an Electron-Ion-Collider. We show that the NLO corrections are sizeable, particularly in the small-xx range. We test the sensitivity of these structure functions on certain quark distributions and compare it to the situation of inclusive DIS and electromagnetic SIDIS.Comment: 17 pages, 5 figure

    Direct Photons at RHIC

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    The PHENIX experiment has measured direct photons in sNN=200\sqrt{s_{NN}} = 200 GeV Au+Au collisions and p+p collisions. The fraction of photons due to direct production in Au+Au collisions is shown as a function of pTp_T and centrality. This measurement is compared with expectation from pQCD calculations. Other possible sources of direct photons are discussed.Comment: 7 pages, 5 figures, presented at Hot Quarks 2004, Taos, N

    Next-to-leading Order Evolution of Transversity Distributions and Soffer's Inequality

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    We present a calculation of the two-loop splitting functions for the evolution of the twist-2 `transversity' parton densities of transversely polarized nucleons. We study the implications of our results for Soffer's inequality for the case of valence quark densities.Comment: 23 Pages, LaTeX, 2 figures as eps files, final, slightly modified version, to appear in Phys. Rev.

    Drell-Yan forward-backward and spin asymmetries for arbitrary vector boson production at next-to-leading order

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    Longitudinally polarized, unpolarized and forward-backward mass differential cross sections for Drell-Yan lepton-pair production by arbitrary vector bosons are calculated in next-to-leading order (NLO) QCD. Analytical results are presented in a form valid for all consistent nn-dimensional regularization schemes, with the mass factorization scheme kept general. NLO predictions for all Drell-Yan type processes (W±W^\pm, ZZ and γ\gamma^*) at BNL's relativistic heavy ion collider (RHIC) are made using polarized parton distributions which fit the recent deep-inelastic scattering data. These are examined as tools in the determination of the polarized parton distributions and the unpolarized uˉ/dˉ\bar{u}/\bar{d} ratio. NLO predictions for the forward-backward lepton asymmetry at Fermilab are made and the precision determination of sin2θW\sin^2 \theta_W from future runs is studied. In all the above, the QCD corrections are found to be significant. An introductory discussion is given of various theoretical issues, such as allowable factorization and regularization schemes, and scale dependences.Comment: 34 pages, figures included, revtex. Some discussions and references added/modified. In more compact form. To appear in Phys. Rev.
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