High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single ${\pi }^{+}$ SIDIS data over a large kinematic range in Bjorken $x$, fractional energy, and transverse momentum of the hadron as well as photon virtualities $Q^2$ ranging from $1–7{\mathrm{GeV}}^2$. In particular, the structure function ratio $F_{LU}^{\sin \varphi }/F_{UU}$ has been determined, where $F_{LU}^{\sin \varphi }$ is a twist-3 quantity that can reveal novel aspects of emergent hadron mass and quark-gluon correlations within the nucleon. The data’s impact on the evolving understanding of the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing transverse momentum dependent parton distribution functions.

• Received 10 January 2021
• Revised 28 September 2021
• Accepted 21 January 2022

DOI:https://doi.org/10.1103/PhysRevLett.128.062005

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Published by the American Physical Society