Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

TL;DR

This paper presents the first measurement of transverse momentum dependence of double spin asymmetries in semi-inclusive pion production from a polarized proton, revealing strong spin-orbit correlations and azimuthal asymmetries.

Contribution

It provides novel experimental data on spin asymmetries and azimuthal modulations in deep inelastic scattering with a longitudinally polarized target.

Findings

Significant non-zero $ ext{sin}2 heta$ single spin asymmetry observed.

Evidence of strong spin-orbit correlations in transversely polarized quarks.

Azimuthal modulations measured over a wide kinematic range.

Abstract

We report the first measurement of the transverse momentum dependence of double spin asymmetries in semi-inclusive production of pions in deep inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Thomas Jefferson National Accelerator Facility (JLab). A significant non-zero $\sin2\phi$ single spin asymmetry was also observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton. The azimuthal modulations of single spin asymmetries have been measured over a wide kinematic range.