50,111 research outputs found

    Does the D−/D+D^-/D^+ production asymmetry decrease at large xFx_F?

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    We have applied the meson cloud model (MCM) to calculate the asymmetries in DD and DsD_s meson production in high energy Σ−\Sigma^--nucleus and π−\pi^--nucleus collisions. We find a good agreement with recent data. Our results suggest that the asymmetries may decrease at large xFx_F.Comment: revised version with new figures and added references to appear in Phys. Rev. Let

    Hadronic form factors and the J/ψJ/\psi secondary production cross section: an update

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    Improving previous calculations, we compute the D+Dˉ→J/ψ+πD + \bar{D} \to J/\psi + \pi cross section using the most complete effective lagrangians available. The new crucial ingredients are the form factors on the charm meson vertices, which are determined from QCD sum rules calculations. Some of them became available only very recently and the last one, needed for our present purpose, is calculated in this work.Comment: 12 pages, 9 eps figure

    ELISPOT assay to measure antigen-specific murine CD8(+) T cell responses.

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    The enzyme-linked immunospot technique (ELISPOT) relies on the visualization of cytokine secretion by individual T cells following in vitro stimulation with antigen. This assay has been developed and standardized for the quantitative detection of antigen-specific CD8(+) T cells in mice subjected to different immunization protocols [J. Immunol. Methods 181 (1995) 45]. We have identified important variables that affect the efficacy of the ELISPOT assay and in this protocol we describe this methodology in detail. As a model, we used the production of interferon-gamma by CD8(+) T cells from peripheral blood, spleen and liver of mice immunized with malaria sporozoites expressing the H-2K(d)-restricted SYVPSAEQI. This protocol has also been used successfully to detect Th1 and Th2 epitope specific CD4(+) T cells
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