2,581 research outputs found
Fermion masses in SUSY SO(10) with type II seesaw: a non-minimal predictive scenario
A predictive framework for fermion masses and mixing is given by the
supersymmetric SO(10) model with one 10, one bar126, one 126 and one 210 Higgs
representations, and type II seesaw dominating the neutrino mass matrix. We
investigate the origin of the tension between this model and lepton mixing data
and refine previous numerical analyses. We discuss an extension of the minimal
model that includes one 120 Higgs chiral superfield representation. This
exhausts the possible renormalizable contributions to the Yukawa sector. In
spite of the increase in the number of parameters the predictivity of the
minimal setting is not spoiled. We argue that the contributions to fermion
masses due to the doublet components of 120 can be naturally small compared to
those of 10 and 126, thus acting as a perturbation in the fermion mass
generation. The antisymmetric nature of the 120 Yukawa coupling affects at
leading order the determination of the mixing angles and it allows to remove
the inconsistencies between predictions and data on the neutrino parameters. An
improvement in the experimental bound on |Ue3| can tell this scenario from the
minimal model.Comment: 11 pages, 3 figures; Note and references added on new KamLAND dat
Beyond homozygosity mapping: family-control analysis based on Hamming distance for prioritizing variants in exome sequencing
A major challenge in current exome sequencing in autosomal recessive (AR) families is the lack of an effective method to prioritize single-nucleotide variants (SNVs). AR families are generally too small for linkage analysis, and length of homozygous regions is unreliable for identification of causative variants. Various common filtering steps usually result in a list of candidate variants that cannot be narrowed down further or ranked. To prioritize shortlisted SNVs we consider each homozygous candidate variant together with a set of SNVs flanking it. We compare the resulting array of genotypes between an affected family member and a number of control individuals and argue that, in a family, differences between family member and controls should be larger for a pathogenic variant and SNVs flanking it than for a random variant. We assess differences between arrays in two individuals by the Hamming distance and develop a suitable test statistic, which is expected to be large for a causative variant and flanking SNVs. We prioritize candidate variants based on this statistic and applied our approach to six patients with known pathogenic variants and found these to be in the top 2 to 10 percentiles of ranks
Application of Hamamatsu MPPC to T2K Neutrino Detectors
A special type of Hamamatsu MPPC, with a sensitive area of 1.3x1.3mm^2
containing 667 pixels with 50x50um^2 each, has been developed for the near
neutrino detector in the T2K long baseline neutrino experiment. About 60 000
MPPCs will be used in total to read out the plastic scintillator detectors with
wavelength shifting fibers. We report on the basic performance of MPPCs
produced for T2K.Comment: Contribution to the proceedings of NDIP 2008, Aix-les-Bains, France,
June 15-20, 200
Impurity Effects on Quantum Depinning of Commensurate Charge Density Waves
We investigate quantum depinning of the one-dimensional (1D) commensurate
charge-density wave (CDW) in the presence of one impurity theoretically.
Quantum tunneling rate below but close to the threshold field is calculated at
absolute zero temperature by use of the phase Hamiltonian within the WKB
approximation. We show that the impurity can induce localized fluctuation and
enhance the quantum depinning. The electric field dependence of the tunneling
rate in the presence of the impurity is different from that in its absence.Comment: 14 pages with 13 figures. Submitted to J. Phys. Soc. Jp
Deformation of Equilibrium Shape of a Vesicle Induced by Injected Flexible Polymers
Using field theoretic approach, we study equilibrium shape deformation of a
vesicle induced by the presence of enclosed flexible polymers, which is a
simple model of drug delivery system or endocytosis. To evaluate the total free
energy of this system, it is necessary to calculate the bending elastic energy
of the membrane, the conformation entropy of the polymers and their
interactions. For this purpose, we combine phase field theory for the membrane
and self-consistent field theory for the polymers. Simulations on this coupled
model system for axiosymmetric shapes show a shape deformation of the vesicle
induced by introducing polymers into it. We examined the dependence of the
stability of the vesicle shape on the chain length of the polymers and the
packing ratio of the vesicle. We present a simple model calculation that shows
the relative stability of the prolate shape compared to the oblate shape.Comment: 5 pages, 3 figure
Numerical computations of facetted pattern formation in snow crystal growth
Facetted growth of snow crystals leads to a rich diversity of forms, and
exhibits a remarkable sixfold symmetry. Snow crystal structures result from
diffusion limited crystal growth in the presence of anisotropic surface energy
and anisotropic attachment kinetics. It is by now well understood that the
morphological stability of ice crystals strongly depends on supersaturation,
crystal size and temperature. Until very recently it was very difficult to
perform numerical simulations of this highly anisotropic crystal growth. In
particular, obtaining facet growth in combination with dendritic branching is a
challenging task. We present numerical simulations of snow crystal growth in
two and three space dimensions using a new computational method recently
introduced by the authors. We present both qualitative and quantitative
computations. In particular, a linear relationship between tip velocity and
supersaturation is observed. The computations also suggest that surface energy
effects, although small, have a larger effect on crystal growth than previously
expected. We compute solid plates, solid prisms, hollow columns, needles,
dendrites, capped columns and scrolls on plates. Although all these forms
appear in nature, most of these forms are computed here for the first time in
numerical simulations for a continuum model.Comment: 12 pages, 28 figure
Performance of Multi-Pixel Photon Counters for the T2K near detectors
We have developed a Multi-Pixel Photon Counter (MPPC) for the neutrino
detectors of T2K experiment. About 64,000 MPPCs have been produced and tested
in about a year. In order to characterize a large number of MPPCs, we have
developed a system that simultaneously measures 64 MPPCs with various bias
voltage and temperature. The performance of MPPCs are found to satisfy the
requirement of T2K experiment. In this paper, we present the performance of
17,686 MPPCs measured at Kyoto University.Comment: 15 pages, 14 figure
Global analysis of neutrino masses, mixings and phases: entering the era of leptonic CP violation searches
We perform a global analysis of neutrino oscillation data, including
high-precision measurements of the neutrino mixing angle theta_13 at reactor
experiments, which have confirmed previous indications in favor of theta_13>0.
Recent data presented at the Neutrino 2012 Conference are also included. We
focus on the correlations between theta_13 and the mixing angle theta_23, as
well as between theta_13 and the neutrino CP-violation phase delta. We find
interesting indications for theta_23< pi/4 and possible hints for delta ~ pi,
with no significant difference between normal and inverted mass hierarchy.Comment: Updated version, including recent data released at the Neutrino 2012
Conference. Some references adde
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