References - Bogoliubov Laboratory of Theoretical Physics - JINR

Figure 5: ALL for h + versus pT measured at √ s =62.4 GeV, showing statistical uncertainties, and
GRSV model predictions.
heavy quark decay, cosmics, and accidentals. The process pp → Z → e + e − constitutes
roughly 6% background for W + , and 30% for W − . We have clear evidence for a W signal
above these backgrounds, and after all cuts, and considering detectors inefficiencies and
W +
dead regions, we expect an uncertainty on the single spin asymmetry δAL ≈ 0.3. With
a few more runs, this uncertainty should reach a few percent.
5 Summary
Results from the RHIC spin experiments, PHENIX and STAR, now pose the tightest
constraints on Δg(x), which is smaller than anticipated from polarized DIS experiments.
There is considerable uncertainty in Δg(x) inthelow-x (x