New Analysis of the Single Transverse-Spin Asymmetry for Hadron Production at RHIC

Abstract

We analyze the single transverse-spin asymmetry (SSAs) for inclusive hadron production in the $pp$ collision at RHIC based on the twist-3 mechanism in QCD. As an origin of SSAs, we take into account of all kinds of pole contributions associated with the twist-3 quark-gluon correlation functions in the polarized proton. By the inclusion of the soft-fermion-pole contribution in addition to the soft-gluon-pole contribution, we find SSAs observed at RHIC are better described for all kinds of mesons. $P_T$-dependence of the asymmetry and the comparison with the FNAL data are also presented.Comment: 16 pages, 6 figures; The figures and the table were changed by correcting the errors in the numerical calculation. Qualitative features stay the same and thus no changes in the text compared with the previous versio