[en] A detailed study of the β^+--α angular correlations in the ⁸Li(β^-) and ⁸B(β⁺) decays was performed. Since these decays proceed to the 2α continuum, detection of both alpha particles enabled determination of various correlations as functions of the final state energy. Analysis of the spectrum of the difference in α-particle energies in coincidence with β^+- particles yields information on the ⁸Be* recoil spectrum, which in turn depends on the β-ν-α angular correlation. The data are consistent with pure Gamow-Teller decay throughout the region 2 MeV < E/sub x/ < 8 MeV, where E/sub x/ is the final state excitation energy in ⁸Be. Experimental results are in good agreement with calculations based on the kinematics of the decay for 2 MeV < E/sub x/ < 10 MeV and when analyzed independent of final state energy. Values integrated over final-state energy are consistent with previous experimental results. The quantity of interest for observing the effects of CVC and second-class currents is delta^- = p/sub -/ - p/sub +/. The experimental results for delta^- show a small (approx. 15% of weak magnetism) deviation from the CVC prediction that is dependent on the final state energy. An effect of this size cannot be interpreted as convincing evidence for the presence of a second-class current or breakdown of CVC. However, the inclusion of the vector second-forbidden terms in the nuclear weak current as predicted by CVC is crucial to obtain even approximate agreement with the experimental results

[en] A major upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility is in progress. Construction began in 2008 and the project should be completed in 2015. The upgrade includes doubling the energy of the electron beam to 12 GeV, the addition of a new fourth experimental hall, and new experimental equipment in three of the experimental halls. A brief overview of this upgrade project is presented along with some highlights of the anticipated experimental program.

[en] Construction of the 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility is presently underway. This upgrade includes doubling the energy of the electron beam to 12 GeV, the addition of a new fourth experimental hall, and the construction of upgraded detector hardware. An overview of this upgrade project is presented, along with highlights of the anticipated experimental program. The 12 GeV upgrade project at Jefferson Lab will enable a powerful new experimental program that will advance our understanding of the quark/gluon structure of hadronic matter, the nature of Quantum Chromodynamics, and the properties of a new extended standard model of particle interactions. Commissioning of the upgraded beam will be begin in 2013, and the full complement of upgraded experimental equipment will be completed in 2015. This unique facility will provide many opportunities for exploration and discovery for a large international community of nuclear scientists.

[en] The recent progress in establishing the existence of finite neutrino masses and mixing between generations of neutrinos has been remarkable, if not astounding. The combined results from studies of atmospheric neutrinos, solar neutrinos, and reactor antineutrinos paint an intriguing picture for theorists and provide clear motivation for future experimental studies. In this review, we summarize the status of experimental and theoretical work in this field and explore the future opportunities that emerge in light of recent discoveries

[en] The Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility provides CW electron beams with high intensity, remarkable stability, and a high degree of polarization. These capabilities offer new and unique opportunities to search for novel particles and forces that would require extension of the standard model. CEBAF is presently undergoing an upgrade that includes doubling the energy of the electron beam to 12 GeV and enhancements to the experimental equipment. This upgraded facility will provide increased capability to address new physics beyond the standard model.

[en] Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were ⁶⁰Ni, ⁵²Cr, ⁵⁶Fe, ⁹²Mo, and ⁹⁶Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but ⁶⁰Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables

[en] The inclusive (e, e') cross section on various nuclei in the quasielastic region (Q²/2Mν/similar to/1) has recently been measured in the range 0.25≤Q²≤3.1. Analysis of these data in the plane-wave impulse approximation allows extraction of a scaling function related to the nucleon momentum distribution. Variation of the scaling function in Q² represents a breakdown of these assumptions in the analysis. Recent theoretical work indicates that the observed scaling violations can be understood as corrections to the impulse approximation and the experimental scaling functions at the highest measured Q² can be in fact be interpreted in terms of nucleon momentum distributions

[en] This latest in a series of workshops on parity-violating electron scattering comes at a momentous time in the history of this subject. The first experiments to determine strange form factors of the nucleon have produced intriguing final results, and several powerful new experiments are now producing data. In addition, the precision of the technique has been improving and new experiments testing the electroweak theory have reported remarkably precise data. There has also been a great deal of progress on both the theory of strange form factors and interpretation of electroweak symmetry tests. (orig.)

[en] The search for fractionally charged particles (FCP) in Nature is ultimately motivated by the belief that the fundamental constituents of the atomic nucleus are quarks, which have charge in integral units of 1/3 of the electronic charge. The reported observation of fractional charge in niobium by a group at Stanford University in 1981 has motivated many new efforts to detect FCP in the past few years. The techniques of accelerator mass spectrometry (AMS) have been successfully applied to this problem at several laboratories. The method generally involves the use of electrostatic analysis systems to separate the FCP from integrally charged ions, since the mass of the FCP is not known a priori. A variety of materials have been searched in these experiments and the most sensitive limits are at concentration levels of less than 10^-18 FCP per atom of host material. (author)

[en] Recent studies of strange quark matrix elements of the nucleon suggest that the effect of strange quarks on nucleon structure is not small. These effects can contribute to the electroweak form factors of the nucleon and can be isolated through measurement of vector and axial vector neutral weak form factors. We evaluate several past and future lepton scattering experiments in terms of their sensitivity to the strange contributions to the neutral weak form factors. (orig.)