Subleading-twist effects in single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized hydrogen target

TL;DR

This paper investigates subleading-twist effects in single-spin asymmetries during semi-inclusive deep-inelastic scattering on polarized hydrogen, revealing significant contributions for nd small for ar mesons, advancing understanding of nucleon spin structure.

Contribution

It provides the first quantitative evaluation of subleading-twist contributions to single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized target.

Findings

Subleading-twist effects are significantly positive for nd dominate previous measurements.

Subleading-twist contributions for ar mesons are small.

Results enhance understanding of nucleon spin dynamics.

Abstract

Single-spin asymmetries in the semi-inclusive production of charged pions in deep-inelastic scattering from transversely and longitudinally polarized proton targets are combined to evaluate the subleading-twist contribution to the longitudinal case. This contribution is significantly positive for (\pi^+) mesons and dominates the asymmetries on a longitudinally polarized target previously measured by \hermes. The subleading-twist contribution for (\pi^-) mesons is found to be small.