Physical Review Letters
We report measurements of single- and double-spin asymmetries for W± and Z/ɣ* boson production in longitudinally polarized p + p collisions at √s = 510 GeV by the STAR experiment at RHIC. The asymmetries for W± 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.
Original Publication Citation
Adamczyk, L., Adkins, J. K., Agakishiev, G., Aggarwal, M. M., Ahammed, Z., Alekseev, I., . . . Collaboration, S. (2014). Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC. Physical Review Letters, 113(7), 072301. doi:10.1103/PhysRevLett.113.072301
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Bültmann, S.; and STAR Collaboration, "Measurement of Longitudinal Spin Asymmetries for Weak Boson Production in Polarized Proton-Proton Collisions at RHIC" (2014). Physics Faculty Publications. 186.