Aspects of $\chi$ and $\psi$ Production in Polarized Proton-Proton Collisions

Abstract

Several topics of relevance to low transverse momentum $\psi$ and ${\chi }_{1,2}(c\overline{c})$ production in polarized proton-proton collisions are discussed. The leading $\mathcal{O}({\alpha }_S^3)$ contributions to the low $p_T$ ${\chi }_1$ production cross-sections via $gg$, $qg$, and $q\overline{q}$ initial states are calculated as well as the corresponding spin-spin asymmetries. We find that ${\chi }_1$ production increases relative to direct $\psi$ and ${\chi }_2$ production, providing up to $25\%$ of the observable $e^{+}{e}^{-}$ pairs arising from $\psi$ decays in $pp$ collisions at $\sqrt{s}=500GeV$. The spin-dependence of ${\chi }_1$ production, however, is much smaller than for either direct $\psi$ or ${\chi }_2$ production and so will likely be far less useful than either process in probing the polarized gluon structure function of the proton. A subset of the $\mathcal{O}({\alpha }_S^3)$ radiative corrections to ${\chi }_2$ production involving initial state quarks are also performed and compared to leading order $gg\to {\chi }_2$ predictions.

Comments: 21 pages + 5 postscript figures (included), OCIP/C-94-1