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Differential cross sections for neutrino-(and antineutrino-) induced nucleon knockout are calculated for neutral-current reactions from nuclei. A relativistic Fermi gas model with binding energy corrections is used. We examine the accuracy with which strange quark axial and vector current parameters can be extracted from both existing and (possible) future experiments. Both high (above 1 GeV) and low (near 150 MeV) neutrino energies and the knockout of neutrons and protons are considered.PACS number(s): 25.30.Pt, 24.85. +p

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We present experimental and theoretical results on bound states in quantum wires (narrow, twodimensional quantum channels). We study rectangular systems of constant width, varying the bend angle. This system is realized by propagation of TE-mode microwaves in flat rectangular waveguides; resonant frequencies for absorption of power are measured for various bend angles, and compared with theoretical results for bound-state (resonant) eigenvalues.

It has been shown that in quantum wires which contain bends there will be one or more bound states for electrons placed in such systems. Bound states have been observed in quantum wires, but detailed mapping of such states is difficult. However, there is a one-to-one correspondence between wave functions of free electrons in two-dimensional ͑2D͒ systems, and electric fields of TE modes in rectangular waveguides with the same cross section as the 2D system. We therefore construct bent waveguides, find the frequencies at which confined EM fields occur, and map out the electromagnetic energy density there. We compare the experimental results with theoretical predictions of bound state energies and eigenfunctions. The geometry has been chosen to correspond to two-dimensional systems for which quantum wire experiments have been carried out. In such systems, we can predict the number and location of the bound states in the system; in addition, we can predict the electric and magnetic fields for the confined TE modes in this system. We show very good agreement between our predictions and experiment for bent waveguides in this geometry.

Recent phenomenological work has examined two different ways of including charge symmetry violation in parton distribution functions. First, a global phenomenological fit to high energy data has included charge symmetry breaking terms, leading to limits on the magnitude of parton charge symmetry breaking. In a second approach, two groups have included the coupling of partons to photons in the QCD evolution equations. One possible experiment that could search for isospin violation in parton distributions is a measurement of the asymmetry in W production at a collider. In this work we include both of the postulated sources of parton charge symmetry violation. We show that, given charge symmetry violation of a magnitude consistent with existing high energy data, the expected W production asymmetries would be quite small, generally less than one percent.