2,254 research outputs found
Deviations from Tri-Bimaximality and Quark-Lepton Complementarity
We study deviations from tri-bimaximality (TBM) and quark-lepton
complementarity (QLC) in a model independent way. The current neutrino
experimental data is well approximated by tri-bimaximal generation mixing but
the QLC relations are not satisfied with each data of 1 level. This
means that there exist deviations from the complementarity. The same fact for
the TBM might be checked in the future neutrino experiments. We discuss such
deviations from the TBM and QLC, simultaneously. A new ratio between the
deviations is introduced, and some interesting points are presented. We also
show predicted correlations among leptonic mixing angles at the points.Comment: 10 pages, 9 figures, final versio
Synthetic Study Of Karlotoxins And Investigation Of Alpha-Diaminoboryl Carbanion Chemistry
Karlotoxins (KmTxs), produced by a toxic marine/estuarine phytoplankton, the dinoflagellate Karlodinium veneficum, are known to be ichthyotoxic, thus being associated with numerous fish deaths events worldwide. They have also been reported to show a variety of biological activities such as hemolytic, cytotoxic, and anti-fungal activities. Recently, the Hamann group successfully assigned the absolute configurations of KmTx2, the first complete structure elucidation among the congeners. In a structural sense, karlotoxins are a family of linear polyketides with three distinctive regions; a bis-tetrahydropyran core fragment, a long, highly oxygenated carbon chain, and a lipophilic chlorodiene unit. Such potent biological activities as well as novel molecular complexity engaged our interest in the synthesis of KmTx molecules in the purpose of supplying more samples for further biological evaluations. We have successfully established a synthetic route to access the C(40-61) B-ring fragment of the KmTx5, a congener of KmTx2, in a twelve-step reaction sequence starting from a reported tetrahydropyranyl intermediate which can be readily prepared from D-mannose in four steps following the literature precedent. α-Boryl carbanion species are known to exhibit excellent olefinating abilities via boron-Wittig reaction. This type of reaction was first reported in the 1960’s, and actively studied mainly by Rathke, Pelter, and Matteson during the last third of the 20th century. We, however, had an impression that this area of chemistry has still been underrepresented in the literature, thus has more room to explore into. Utilizing the α-diaminobory carbanion-mediated one-pot olefination protocols we have developed, we successfully prepared a variety of substituted acrylonitriles, including tetrasubstituted alkenes, by olefinating aldehydes and ketones. We have also demonstrated a useful application of the α-boryl carbanion species for the synthesis of 2-aminoquinoline-based alkaloids
Higgs response and pair condensation energy in superfluid nuclei
The pairing correlation in nuclei causes a characteristic excitation, known
as the pair vibration, which is populated by the pair transfer reactions. Here
we introduce a new method of characterizing the pair vibration by employing an
analogy to the Higgs mode, which emerges in infinite superconducting/superfluid
systems as a collective vibrational mode associated with the amplitude
oscillation of the Cooper pair condensate. The idea is formulated by defining a
pair-transfer probe, the Higgs operator, and then describing the linear
response and the strength function to this probe. We will show that the pair
condensation energy in nuclei can be extracted with use of the strength sum and
the static polarizability of the Higgs response. In order to demonstrate and
validate the method, we perform for Sn isotopes numerical analysis based the
quasi-particle random phase approximation to the Skyrme-Hartree-Fock-Bogoliubov
model. We discuss a possibility to apply this new scheme to pair transfer
experiment.Comment: 31 pages, 9 figure
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