Double Spin Asymmetries in P-wave Charmonium Hadroproduction

Abstract

We discuss the double spin asymmetries in P-wave charmonium hadroproduction with non-zero transverse momenta at fixed target energies, $\sqrt{s}\simeq 40$ GeV, within the framework of the NRQCD factorization approach. The size of the asymmetries and the projected statistical errors in a future option of HERA with longitudinally polarized protons scattering off a polarized target (HERA-$\vec{N}$) are calculated. Measurements of the ${\chi }_{c1}$ and ${\chi }_{c2}$ decays into dilepton plus photon should allow to distinguish between different parametrizations for the polarized gluon distribution in the proton. At higher energies ($\sqrt{s}=200$ GeV) the situation appears less favourable with the presently envisaged integrated luminosities of the polarized RHIC collider.

Comments: 10 pages, LaTeX, with 5 eps figs included with epsfig.sty