Transverse spin and momentum correlations in quantum chromodynamics

摘要

The naive time reversal odd (`T-odd') parton distribution and fragmentation functions are explored. We use the spectator model framework to study flavour dependence of the Boera€“Mulders $(h_{1}^{a?￥})$ and Sivers $(f_{1 ext{T}}^{a?￥})$ functions as well as the `T-even' but chiral odd function $h_{1 ext{L}}^{a?￥}$. These transverse momentum-dependent parton distribution functions are of significance for the analysis of azimuthal asymmetries in semi-inclusive deep inelastic scattering, as well as for the overall physical understanding of the distribution of transversely polarized quarks in unpolarized hadrons. In this context we also consider the Collins mechanism and the fragmentation function $H_{1}^{a?￥}$. As a by-product of this analysis we calculate the leading twist unpolarized cos(2e???) asymmetry, and sin(2e???) single spin asymmetry for a longitudinally polarized target in semi-inclusive deep inelastic scattering.