arXiv:hep-ph/0210371·v1·High Energy Physics — Phenomenology
Transverse single spin asymmetries in Drell-Yan processes
M. Anselmino (1)🇮🇹 · U. D'Alesio (2)🇮🇹 · F. Murgia (2) ((1) University and INFN, Torino, Italy, (2) University and INFN, Cagliari, Italy)🇮🇹
Abstract
Recently, it has been shown, contrary to previous beliefs, that the k_T distribution of quarks in a transversely polarized proton can be asymmetric. This ``Sivers effect'' had already been used to explain transverse single spin asymmetries (SSA) observed in inclusive pion production, p(transv. polarized) p --> pion + X and p-bar(transv. polarized) p --> pion + X. In such channels, however, other mechanisms, like the ``Collins effect'' (a k_T asymmetric fragmentation of a transversely polarized quark into pions), may generate SSA. The Sivers asymmetry is used here to compute SSA in Drell-Yan processes; in this case, by considering the differential cross-section in the lepton-pair invariant mass, rapidity and transverse momentum, other mechanisms which may originate SSA cannot contribute. Estimates for RHIC experiments are given.
Comments: LaTeX, 24+1 pages, 7 ps figures, uses epsfig.sty