TMDs and SSAs in hadronic interactions

Abstract

We present an overview on the current experimental and phenomenological status of transverse single spin asymmetries (tSSAs) in proton-proton collisions. In particular, we focus on large-$p_T$ inclusive pion, photon, jet, pion-jet production and Drell-Yan processes. For all of them theoretical estimates are given in terms of a generalised parton model (GPM) based on a transverse momentum dependent (TMD) factorisation scheme. Comparisons with the corresponding results in a collinear twist-3 formalism and in a modified GPM approach are also made. On the experimental side, a selection of the most interesting and recent results from RHIC is presented.

Comments: 19 pages, 20 figures with 28 ps files, uses svjour.cls. Invited review contribution to the Special Issue on "3D Structure of the Nucleon" to be published in the European Physical Journal A - Hadrons and Nuclei