Transversity and Spin Structure Functions

TL;DR

This paper discusses recent experimental measurements of spin asymmetries in deep-inelastic scattering, revealing insights into the transverse spin structure of nucleons, including quark orbital angular momentum and fragmentation functions.

Contribution

It reviews pioneering measurements of transverse spin asymmetries and evaluates their implications for understanding the nucleon's transverse spin and orbital angular momentum.

Findings

Evidence for nonzero Sivers asymmetries indicating quark orbital angular momentum

Properties of the Collins fragmentation function are characterized

First experimental results on transverse spin asymmetries are presented

Abstract

Measurements of single-spin asymmetries for semi-inclusive electro-production of pions and kaons in deep-inelastic scattering with transverse target polarization open a new window on the transverse quark and gluon structure of the nucleon. The first experimental results from such measurements as well as experiments in progress are discussed. Properties of the spin-dependent Collins fragmentation function and prospects for extracting the transversity are reviewed and evidence for nonzero Sivers asymmetries as manifestations of quark orbital angular momentum is evaluated.