Search

The Fermilab E866/NuSea Collaboration has measured the Drell‐Yan dimuon cross sections in 800 GeV/c proton‐proton and proton‐deuterium collisions. This is the first measurement of the absolute Drell‐Yan cross section in proton‐proton collisions over a broad kinematic region and the most extensive study to date of the Drell‐Yan cross section in proton‐deuterium collisions. The Drell‐Yan mechanism is sensitive to both the beam and target parton distributions. In particular, with the kinematics of the E866/NuSea data, the Drell‐Yan mechanism is sensitive to the target antiquark distributions at low and intermediate Bjorken‐x and to the beam quark distributions at high‐x. Approximately 55K proton‐proton and 121K proton‐deuterium Drell‐Yan events over the longitudinal momentum fraction (Feynman‐x) range −0.05 < xF < 0.8 and the mass ranges 4.2 < Mμ+μ− < 8.7 GeV and 10.85 < M < 16.85 GeV are included. The data analysis will be described, and the doubly‐differential M3d2σ/dMdxF, and triply‐differential cross sec...

Despite QCD’s success in describing many aspects of the strong interaction, an adequate description of quarkonia production is still missing. While the production of the heavy QQ pair from gluon-gluon fusion or quark-antiquark annihilation can be perturbatively calculated, the long-distance process involving the formation of the bound states is presently not amenable to calculation. Various models of quarkonia production have been proposed, including color singlet and octet components, and these models make predictions for polarization of the quarkonia. FNAL E866 has measured the polarization of quarkonia production in the ψ and Υ families. The data show that the Υ(1S) is produced with only slight polarization, and only at large fractional longitudinal momentum (xF) or large transverse momenta (pT), while the Υ(2S) and (3S) states are completely polarized. In the ψ family, the J/ψ is produced with only slight polarization, which changes from transverse to longitudinal as a function of increasing xF. Thes...

Precise measurements of J/Ψ, Ψ′ and Drell-Yan production in 800 GeV/c p-A collisions are reported. The observed J/Ψ and Ψ′ suppression is smallest and nearly constant for −0.1