Aspects of heavy quark production in polarized proton-proton collisions

We examine the spin-dependence of b-quark production at large transverse momentum in polarized proton-proton collisions. The leading-order (LO) 2 → 2 subprocesses, g+g → Q+Q and q+q → Q+Q have a large ‘analyzing power’, as measured by the average spin-spin asymmetry <âLL>, at large pT , approaching −100%. The contributions from next-to-leading order (NLO) 2 → 3 processes are also discussed and found to be dominated at large transverse momentum by subprocesses with a large and positive partonic level spin asymmetry leading to strong cancellations with the LO predictions. The results suggest that bquark production might constitute an interesting test of the spin-dependence of NLO QCD but they also point up the importance of a full calculation of the complete O(α3S) spin-dependent corrections for a successful extraction of the polarized gluon distribution. Similarities to gluino pair production are also briefly discussed.