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In a class of supersymmetric flavor models predictions are based on residual symmetries of some subsectors of the theory such as those of the charged leptons and neutrinos. However, the vacuum expectation values of the so-called flavon fields generally modify the Kähler potential of the setting, thus changing the predictions. We derive simple analytic formulae that allow us to understand the impact of these corrections on the predictions for the masses and mixing parameters. Furthermore, we discuss the effects on the vacuum alignment and on flavor changing neutral currents. Our results can also be applied to non-supersymmetric flavor models. © 2013 Elsevier B.V.

The well-known Giudice-Masiero mechanism explains the presence of a μ term of the order of the gravitino mass, but does not explain why the holomorphic mass term is absent in the supzerpotential. We discuss anomaly-free discrete symmetries which are both compatible with SU(5) unification of matter and the Giudice-Masiero mechanism, i.e. forbid the μ term in the superpotential while allowing the necessary Kähler potential term. We find that these are ZMR symmetries with the following properties: (i) M is a multiple of four; (ii) the Higgs bilinear H uH d transforms trivially; (iii) the superspace coordinate θ has charge M/4 and, accordingly, the superpotential has charge M/2; (iv) dimension-five proton decay operators are automatically absent. All ZMR symmetries are anomaly-free due to a non-trivial transformation of a Green-Schwarz axion, and, as a consequence, a holomorphic μ term appears at the non-perturbative level. There is a unique symmetry that is consistent with the Weinberg operator while there is a class of ZMR symmetries which explain suppressed Dirac neutrino masses. © 2012 Elsevier B.V.

We discuss the predictive power of supersymmetric models with flavor symmetries, focusing on the lepton sector of the standard model. In particular, we comment on schemes in which, after certain 'flavons' acquire their vacuum expectation values (VEVs), the charged lepton Yukawa couplings and the neutrino mass matrix appear to have certain residual symmetries. In most analyses, only corrections to the holomorphic superpotential from higher-dimensional operators are considered (for instance, in order to generate a realistic θ 13 mixing angle). In general, however, the flavon VEVs also modify the Kähler potential and, therefore, the model predictions. We show that these corrections to the naive results can be sizable. Furthermore, we present simple analytic formulae that allow us to understand the impact of these corrections on the predictions for the masses and mixing parameters. © 2012.

We discuss, using the Hilbert basis method, how to efficiently construct a complete basis for D-flat directions in supersymmetric Abelian and non-Abelian gauge theories. We extend the method to discrete (R and non-R) symmetries. This facilitates the construction of a basis of all superpotential terms in a theory with given symmetries.

Recently, sulfur-containing copolyimides have attracted increasing attention as membrane materials for the separation of gaseous, vaporous, or liquid mixtures because of their superior separation properties. Therefore, a novel sulfur-containing copolyimide based on 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, 4,4′-diaminodiphenylsulfide, and 3,5-diaminobenzoic acid was synthesized, characterized, and extensively investigated in toluene/ n-decane pervaporation experiments. To characterize the separation properties of the copolyimide, the flux and selectivity were determined with separation mixtures between 60 and 80 wt % toluene. The separation temperature was varied between 70 and 110°C. Thereby, we observed that when the temperature was increased from 70 to 90°C, the flux and selectivity did not change significantly. In contrast, a temperature change from 90 to 110°C caused an extensive increase in the flux. The most significant change was found for an 80 wt % toluene mixture, where an increase from 1.9 to 7 kg·μm·m−2·h−1 was observed. Simultaneously, the selectivity which is a measure of the quality of the separation (α) decreased from α = 11.8 to α = 9.3. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

The formation of Agn clusters and Agn+ cluster ions under bombardment of a silver surface with SF5+ and Xe+ projectile ions was investigated experimentally. In order to obtain information about the relative abundance of clusters among the flux of sputtered particles independent of their charge state, mass spectra of both secondary ions and sputtered neutral particles were recorded. The neutral species were post-ionized prior to mass analysis by means of photo-ionization using an intense UV laser at a wavelength of 193 nm. It is found that measured Agn+ signals increase significantly if SF5+ projectiles are used instead of rare gas (Ar+ or Xe+) ions of the same kinetic impact energy. The signals of neutral Ag atoms and Agn clusters, on the other hand, exhibit only a relatively small increase, thus indicating that the enhancement observed for the secondary ions is predominantly caused by an increased ionization probability of sputtered particles under SF5+ bombardment rather than by enhanced partial sputtering yields. While the transition from Ar+ to Xe+ projectiles leads to a drastic increase of the relative abundance of larger clusters in the spectrum, practically no such effect can be detected for the transition from Ar+ to SF5+. This finding shows that the use of polyatomic SF5 projectiles does not lead to a higher efficiency in producing sputtered clusters. [Copyright &y& Elsevier]