The electric form factor of the neutron was determined from studies of the reaction ${\mathrm{}}^3\overrightarrow{\mathrm{He}}(\overrightarrow{e},e^{\prime }n)pp$ in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the $Q^2$ range over which it is known, we find $G_E^n=0.0236\pm 0.0017(\mathrm{stat})\pm 0.0026(\mathrm{syst})$, $0.0208\pm 0.0024\pm 0.0019$, and $0.0147\pm 0.0020\pm 0.0014$ for $Q^2=1.72$, 2.48, and $3.41{\mathrm{GeV}}^2$, respectively.

We present results for spectroscopic factors of the outermost shells in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, which have been derived from the comparsion between the available quasielastic (e,e’p) data from NIKHEF-K and the corresponding calculated cross sections obtained within a fully relativistic formalism. We include exactly the effect of Coulomb disortion on the electron wave functions and discuss its role in the extraction of the spectroscopic factors from experiment. Without any adjustable parameter, we find spectroscopic factors of about 70%, consistent with theoretical predictions. We compare our results with previous relativistic and nonrelativistic analyses of (e,e’p) data. In addition to Coulomb distortion effects, we discuss different choices of the nucleon current operator and also analyze the effects due to the relativistic treatment of the outgoing-distorted and bound nucleon wave functions.

We have measured the proton recoil polarization in the ${}^4\mathrm{H}\mathrm{e}(\overrightarrow{e},e^{\prime }\overrightarrow{p}){}^4\mathrm{H}$ reaction at $Q^2=0.5$, 1.0, 1.6, and $2.6(\mathrm{G}\mathrm{e}\mathrm{V}/c{)}^2$. The measured ratio of polarization transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a medium modification of the proton form factors predicted by a quark-meson coupling model. In addition, the measured induced polarizations agree reasonably well with the fully relativistic calculation indicating that the treatment of final-state interactions is under control.

Ultrasound computed tomography (USCT) is a non-invasive imaging technique that provides information about the acoustic properties of soft tissues in the body, such as the speed of sound (SS) and acoustic attenuation (AA). Knowledge of these properties can improve the discrimination between benign and malignant masses, especially in breast cancer studies. Full wave inversion (FWI) methods for image reconstruction in USCT provide the best image quality compared to more approximate methods. Using FWI, the SS is usually recovered in the time domain, and the AA is usually recovered in the frequency domain. Nevertheless, as both properties can be obtained from the same data, it is desirable to have a common framework to reconstruct both distributions. In this work, an algorithm is proposed to reconstruct both the SS and AA distributions using a time domain FWI methodology based on the fractional Laplacian wave equation, an adjoint field formulation, and a gradient-descent method. The optimization code employs a Compute Unified Device Architecture version of the software k-Wave, which provides high computational efficiency. The performance of the method was evaluated using simulated noisy data from numerical breast phantoms. Errors were less than 0.5% in the recovered SS and 10% in the AA.

Proton recoil polarization was measured in the quasielastic ${}^4\mathrm{He}(\overrightarrow{e},e^{\prime }\overrightarrow{p}){}^3\mathrm{H}$ reaction at $Q^2=0.8$ and $1.3(\mathrm{GeV}/c{)}^2$ with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the ${}^1\mathrm{H}(\overrightarrow{e},e^{\prime }\overrightarrow{p})$ reaction, contradicting a relativistic distorted-wave approximation and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton.