Fritzsch Texture in SUSY-SO(10) with Large Neutrino Mixing

Fritzsch's texture is imposed on {\em all} mass matrices in a SUSY-SO(10) via a family $U(1)_{PQ}$ symmetry. The observed charged fermion parameters fix the $\nu$-masses and mixing, while the later are evolved from the GUT scale to low energies using the RG. Large $\sin^2 2{\theta}_{12}$ results. As in a SUSY-GUT no intermediate scale is allowed, the RH-neutrino scale is the unification one and this gives in our model $\Delta m_{12}^2 \approx {10}^{-10} eV^2$, in accordance with the vacuum oscillation solution to the solar-$\nu$ puzzle.Comment: 10 pages (standard LaTeX, 3 figures included as postscript files), WU B 93-1

Elastic scattering and electronic excitation in positron interactions with neon

Abstract We report measurements of low energy positron scattering from neon, with the first measurements of absolute differential cross sections (DCSs) and of state-selective electronic excitation. These measurements are compared to calculations using the relativistic optical potential (ROP) technique, as well as other recently published theoretical calculations. At the lowest energies, experimental DCS data are fitted to extract scattering phase shifts, which can be compared to theoretical values and also used to generate DCS values over the full angular range. For the most part we find good accord in the two descriptions of the scattering processes, with some key disagreements. An analysis of possible sources of systematic error has also been presented, in light of the discrepancies.</jats:p