Beam-recoil transferred polarizations for the exclusive $\overrightarrow{e}p\to e^{\text{'}}{K}^{+}\overrightarrow{\Lambda },{\overrightarrow{\Sigma }}^0$ reactions have been measured using the Continuous Electron Beam Accelerator Facility's large acceptance spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. 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 ${\mathrm{GeV}}^2$, 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 semiclassical partonic models are made to probe the underlying reaction mechanism and the $s\overline{s}$ quark-pair creation dynamics.

We report the results of a new measurement of spin structure functions of the deuteron in the region of moderate momentum transfer $[Q^2=0.27\mathrm{}–1.3(\mathrm{GeV}{/c)}^2]$ and final hadronic state mass in the nucleon resonance region $(W=1.08\mathrm{}–2.0\mathrm{GeV}).\mathrm{}$ We scattered a 2.5 GeV polarized continuous electron beam at Jefferson Lab off a dynamically polarized cryogenic solid state target ${(}^{15}{\mathrm{ND}}_3)$ and detected the scattered electrons with the CEBAF large acceptance spectrometer. From our data, we extract the longitudinal double spin asymmetry $A_{||}$ and the spin structure function $g_1^d.$ Our data are generally in reasonable agreement with existing data from SLAC where they overlap, and they represent a substantial improvement in statistical precision. We compare our results with expectations for resonance asymmetries and extrapolated deep inelastic scaling results. Finally, we evaluate the first moment of the structure function $g_1^d$ and study its approach to both the deep inelastic limit at large $Q^2$ and to the Gerasimov-Drell-Hearn sum rule at the real photon limit ${(Q}^2\to 0).$ We find that the first moment varies rapidly in the $Q^2$ range of our experiment and crosses zero at $Q^2$ between 0.5 and $0.8(\mathrm{GeV}{/c)}^2,$ indicating the importance of the $\Delta$ resonance at these momentum transfers.

Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CEBAF Large Acceptance Spectrometer detector and the tagged photon beam at the Thomas Jefferson National Accelerator Facility. The data cover photon energies between $0.5$ and $3.0\mathrm{GeV}$ and center-of-mass proton scattering angles $10°–160°$. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well described by the nonperturbative quark gluon string model.

A phenomenological model is developed for describing the production of π+ π−pairs on a proton by virtual photons in the energy region of nucleon-resonance excitation.The cross sections are...