Do we understand the single-spin asymmetry for inclusive production in pp collisions?
Centre de Physique Théorique, UMR 6207, CNRS-Luminy Case 907, 13288, Marseille Cedex 9, France
The cross section data for inclusive production in pp collisions is considered in a rather broad kinematic region in energy , Feynman variable x F and transverse momentum p T. The analysis of these data is done in the perturbative QCD framework at the next-to-leading order. We find that they cannot be correctly described in the entire kinematic domain and this leads us to conclude that the single-spin asymmetry, A N for this process, observed several years ago at FNAL by the experiment E704 and the recent result obtained at BNL-RHIC by STAR, are two different phenomena.
© Springer-Verlag, 2004