Beam-Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive $\vec{e}p \to e'K^+\vec{\Lambda}$ and $\vec{e}p \to e'K^+\vec{\Sigma}^0$ Reactions at CLAS

TL;DR

This paper reports new measurements of beam-recoil polarization transfer in exclusive kaon electroproduction reactions at Jefferson Lab, covering a broad kinematic range and providing the first data for the $K^+\Sigma^0$ channel, to study reaction mechanisms and resonance contributions.

Contribution

It presents the first-ever data for the $K^+\Sigma^0$ electroproduction channel and expands existing measurements, enabling detailed comparison with theoretical models of reaction mechanisms.

Findings

Data show sensitivity to s-channel resonance contributions.

Results support semi-classical partonic models of the reaction.

New measurements span a wide kinematic range.

Abstract

Beam-recoil transferred polarizations for the exclusive $\vec{e}p \to e'K^+ \vec{\Lambda},\vec{\Sigma}^0$ reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754 GeV that span a range of momentum transfer $Q^2$ from 0.7 to 5.4 GeV$^2$, invariant energy $W$ from 1.6 to 2.6 GeV, and the full center-of-mass angular range of the $K^+$ meson. These new data add to the existing CLAS $K^+\Lambda$ measurements at 2.567 GeV, and provide the first-ever data for the $K^+\Sigma^0$ channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to s-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semi-classical partonic models are made to probe the underlying reaction mechanism and the $s\bar{s}$ quark-pair creation dynamics.