Measurement of Longitudinal Spin Asymmetries for Weak Boson Production in Polarized Proton-Proton Collisions at RHIC

• Main Authors: Balewski, Jan T. (Contributor), Stevens, Justin (Contributor), van Nieuwenhuizen, Gerrit Jan (Contributor)
• Other Authors: Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2014-10-29T16:18:58Z.
• Subjects: Article
• Online Access: Get fulltext

We report measurements of single- and double-spin asymmetries for W[superscript ±] and Z/γ[superscript ∗] boson production in longitudinally polarized p + p collisions at √s = 510  GeV by the STAR experiment at RHIC. The asymmetries for W[superscript ±] were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton's polarized quark distributions at the scale of the W mass. The results are compared to theoretical predictions, constrained by polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range 0.05 < x < 0.2.
Brookhaven National Laboratory
Lawrence Berkeley National Laboratory
United States. Dept. of Energy. Office of Nuclear Physics
United States. Dept. of Energy. Office of High Energy Physics
National Science Foundation (U.S.)