Dihedral Families of Quarks, Leptons and Higgs Bosons

We consider finite groups of small order for family symmetry. It is found that the binary dihedral group Q_6, along with the assumption that the Higgs sector is of type II, predicts mass matrix of a nearest neighbor interaction type for quarks and leptons. We present a supersymmetric model based on Q_6 with spontaneously induced CP phases. The quark sector contains 8 real parameters with one independent phase to describe the quark masses and their mixing. Predictions in the |V_{ub}|-bar{eta}, |V_{ub}|-sin 2 beta(phi_1) and |V_{ub}|-|V_{td}/V_{ts}| planes are given. The lepton sector contains also 9 parameters. A normal as well as an inverted spectrum of neutrino masses is possible, and we compute V_{e3}. We find that |V_{e3}|^2 > 10^{-4} in the case of a normal spectrum, and |V_{e3}|^2 >8 10^{-4} in the case of an inverted spectrum. It is also found that Q_6 symmetry forbids all Baryon number violating terms of d=4, and the contributions to EDMs from the A terms vanish in this model.Comment: 27 pages, 8 figure

Supersymmetry, local horizontal unification, and a solution to the flavor puzzle

Supersymmetric gauge models with local horizontal symmetries are known to generate large flavor changing neutral current effects induced by supersymmetry breaking D-terms. We show how the presence of a U(1) gauge symmetry solves this problem. We then construct a realistic gauge model with SU(2)_H x U(1)_H as the local horizontal symmetry and suggest that the U(1)_H factor may be identified with the anomalous U(1) induced by string compactification. This model explains the observed hierarchies among the quark masses and mixing angles, accommodates naturally the solar and atmospheric neutrino data, and provides simultaneously a solution to the supersymmetric flavor problem. The model can be excluded if the rare decay \mu --> e \gamma is not observed in the current round of experiments.Comment: 10 pages in RevTe

Neutrino Masses and Mixings in a Minimal SO(10) Model

We consider a minimal formulation of SO(10) Grand Unified Theory wherein all the fermion masses arise from Yukawa couplings involving one 126 and one 10 of Higgs multiplets. It has recently been recognized that such theories can explain, via the type-II seesaw mechanism, the large \nu_\mu - \nu_\tau mixing as a consequence of b-tau unification at the GUT scale. In this picture, however, the CKM phase \delta lies preferentially in the second quadrant, in contradiction with experimental measurements. We revisit this minimal model and show that the conventional type-I seesaw mechanism generates phenomenologically viable neutrino masses and mixings, while being consistent with CKM CP violation. We also present improved fits in the type-II seesaw scenario and suggest fully consistent fits in a mixed scenario.Comment: 27 pages, 13 eps figures, revtex4; references added, some minor correction

Impact Welding in a Variety of Geometric Configurations

Magnetic pulse welding is an electromagnetically assisted high strain rate impact welding technology. The physical principle is similar to explosive welding and it also belongs to solid state impact welding. This high velocity oblique impact welding has been applied to various lap joint configurations. Three different geometric configurations on plate-to-plate welding were studied in this paper. They are direct lap joint, pre-flange lap joint, and lap joint with embedded wires. All of the three welding configurations have been used to provide metallurgical bonds between both similar and dissimilar metal pairs. The welded materials include copper alloy, aluminium alloy, and steels. The plates are centimeter or more thick and often centimeter in extent. The critical welding process parameters were instrumentally investigated by Rogowski Coil and Photon Doppler Velocimetry. Metallographic analysis of the welded interface showed refined grain structure. The mechanical properties of the welded plates were studied by lap shearing, peeling and nano-indentation tests. The test results showed that the impact welded interface has a much greater micro-hardness and fracture toughness than the base metals

Natural Gauge Hierarchy in SO(10)

It is shown that a natural gauge hierarchy and doublet-triplet splitting can be achieved in SO(10) using the Dimopoulos-Wilczek mechanism. Artificial cancellations (fine-tuning) and arbitrary forms of the superpotential are avoided, the superpotential being the most general compatible with a symmetry. It is shown by example that the Dimopoulos-Wilczek mechanism can be protected against the effects of higher-dimension operators possibly induced by Planck-scale physics. Natural implementation of the mechanism leads to an automatic Peccei-Quinn symmetry. The same local symmetries that would protect the gauge hierarchy against Planck-scale effects tend to protect the axion also. It is shown how realistic quark and lepton masses might arise in this framework. It is also argued that ``weak suppression'' of proton decay can be implemented more economically than can ``strong suppression'', offering some grounds to hope (in the context of SO(10)) that proton decay could be seen at Superkamiokande.Comment: 26 pages in plain LaTeX, 5 figures available on request, BA-94-0

Mayer-Rokitansky-Kuster-Hauser syndrome with gonadohypoplasia:a rare case report

MRKH (Mayer Rokitansky Kuster Hauser) syndrome is a congenital abnormality seen in one out of 5,000 women characterized by the agenesis of the vagina, cervix, and uterus. It is also associated with kidney, bone and hearing difficulties. The ovaries are present with a normal function similar to that of a healthy reproductive woman’s by producing eggs and female hormones. Chromosomes are the normal 46xx female karyotype. We report this rare syndrome in a 26–year-old female where she had presented with complaints of absence of uterus with the absence of left kidney. She didn’t attain menarchy, secondary sexual characters are well developed. Small right ovarian follicular cyst with a rim of ovarian tissue was observed. She had undergone vaginoplasty

Growth rate of YBCO single grains containing Y-2411(M)

Y-Ba-Cu-O (YBCO) single grains have the potential to generate large trapped magnetic fields for a variety of engineering applications, and research on the processing and properties of this material has attracted world-wide interest. In particular, the introduction of flux pinning centres to the large grain microstructure to improve its current density, Jc, and hence trapped field, has been investigated extensively over the past decade. Y 2Ba4CuMOx [Y-2411(M)], where M = Nb, Ta, Mo, W, Ru, Zr, Bi and Ag, has been reported to form particularly effective flux pinning centres in YBCO due primarily to its ability to exist as nano-size inclusions in the superconducting phase matrix. However, the addition of the Y-2411(M) phase to the precursor composition complicates the melt-processing of single grains. We report an investigation of the growth rate of single YBCO grains containing Y-2411(Bi) phase inclusions and Y2O3. The superconducting properties of these large single grains have been measured specifically to investigate the effect of Y2O3 on broadening the growth window of these materials