Transverse-target-spin asymmetry in exclusive $\omega$-meson electroproduction

TL;DR

This paper reports on the measurement of transverse-target-spin asymmetries in exclusive omega-meson electroproduction, providing insights into the underlying nucleon structure and meson production mechanisms.

Contribution

It presents the first detailed measurement of azimuthal asymmetries in omega-meson electroproduction with transverse polarization, including separation into longitudinal and transverse components.

Findings

Data favor a positive πω transition form factor.

Results support the pion pole contribution in the phenomenological model.

Measurements cover the entire kinematic range and specific bins.

Abstract

Hard exclusive electroproduction of $\omega$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive $\pi\omega$ transition form factor.