Complete Study of Hadroproduction of a ϒ Meson Associated with a Prompt J/ψ.

We present the first complete study of ϒ and prompt J/ψ production from single-parton scattering, including the complete O(α_{S}^{6}) color-singlet contribution, the O(α_{S}^{2}α^{2}) electroweak contribution, and 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 the D0 Collaboration of prompt J/ψ and ϒ simultaneous production at the Tevatron. With our complete evaluation, we are able to refine the determination of the double-parton scattering contribution made by the D0 Collaboration. We find that the effective cross section characterizing the importance of double-parton scatterings is σ_{eff}≤8.2  mb at 68% confidence level from the D0 measurement.