The Gluon Sivers Distribution in D production at RHIC

Abstract

The single transverse spin asymmetry in D meson production at RHIC can provide a clean measure of the gluon Sivers distribution function. At intermediate rapidity, D production is largely dominated by the elementary gg -> c c-bar channel, where there cannot be any transverse spin transfer. Therefore, any transverse single spin asymmetry observed for D's produced in polarized proton-proton interactions can only originate from the Sivers effect in the gluon distribution functions. A sizeable transverse single spin asymmetry measured by PHENIX or STAR experiments would then give direct information on the size of the gluon Sivers distribution function.

Comments: 4 pages, 2 postscript figures, talk given by M. Boglione at SPIN04, 16th International Spin Physics Symposium, Trieste, Oct. 11-16 2004