2,289 research outputs found

    Complete Study of Hadroproduction of a Υ\Upsilon Meson Associated with a Prompt J/ψJ/\psi

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    We present the first complete study of Υ\Upsilon and prompt J/ψJ/\psi production from single-parton scattering, including the complete O(αS6)\mathcal{O}(\alpha_S^6) color-singlet contribution, the O(αS2α2)\mathcal{O}(\alpha_S^2\alpha^2) electroweak contribution, the complete nonrelativistic S-wave and P-wave color-octet contribution as well as the feeddown contribution. Our study was motivated by the recent evidence reported by D0 Collaboration of prompt J/ψJ/\psi and Υ\Upsilon simultaneous production at the Tevatron. With our complete evaluation, we are able to refine the determination of the double parton scattering contribution made by D0 Collaboration. We find that the effective cross section characterizing the importance of double-parton scatterings is σeff≤8.2\sigma_{\rm eff}\le 8.2 mb at 68%68\% confidence level from the D0 measurement.Comment: 11 pages, 4 figures, 4 tables; v2: journal version, update the references and fix a few typo

    Feynman Rules for the Rational Part of One-loop QCD Corrections in the MSSM

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    The complete set of Feynman rules for the rational part R of QCD corrections in the MSSM are calculated at the one-loop level, which can be very useful in the next-to-leading order calculations in supersymmetric models. Our results are expressed in the 't Hooft-Veltman regularization scheme and in the Four Dimensional Helicity scheme with non-anticommutating and anticommutating γ5\gamma_5 strategies.Comment: version for publication, 50 pages, 6 figure
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