Beam-Recoil Polarization Transfer in the Nucleon Resonance Region in the Exclusive $\vec{e}p\to e^{\prime }{K}^{+}\vec{\hat{I}}›$ and $\vec{e}p\to e^{\prime }{K}^{+}\vec{\hat{I}}{\pounds }^0$ Reactions at CLAS

Abstract

Beam-recoil transferred polarizations for the exclusive $\vec{e}p\to e^{\prime }{K}^{+}\vec{\hat{I}}›,\vec{\hat{I}}{\pounds }^0$ 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 $K^{+}\hat{I}›$ measurements at 2.567 GeV, and provide the first-ever data for the $K^{+}\hat{I}{\pounds }^0$ 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.

48 pages, 22 figures