Single-Transverse Spin Asymmetry in Semi-Inclusive Deep Inelastic Scattering

Abstract

We study the single-transverse spin asymmetry in semi-inclusive hadron production in deep inelastic scattering. We derive the leading contribution to the asymmetry at moderate transverse momentum $P_{h\perp}$ of the produced hadron in terms of twist-three quark-gluon correlation functions, and compare with the approach based on the factorization at fixed transverse momentum involving the asymmetric transverse-momentum and spin-dependent quark distribution. We verify that the two approaches yield identical results in this regime. By a comparison with our earlier calculations for the single-spin asymmetry in the Drell-Yan process we recover the well-established process-dependence of the time-reversal-odd transverse-momentum-dependent quark distributions that generate single-spin phenomena.

Figures (3)

• Figure 1: A generic Feynman diagram contributing to the Sivers-type single-transverse-spin asymmetry for inclusive hadron production in semi-inclusive deep inelastic scattering.
• Figure 2: Feynman diagrams making soft-pole contributions to the single-transverse-spin dependent cross section. The bars indicate the propagators where a soft pole arises. The "mirror" diagrams for which the additional initial gluon attaches on the right of the cut are not shown, but are included in the calculations.
• Figure 3: Same as Fig. 2, but for the hard-pole contributions.