602 research outputs found
Poly-instanton axion inflation
We investigate the axion inflation model derived by poly-instanton effects in
type II superstring theories. Poly-instanton effects are instanton effects
corrected by another instanton and it can generate the modulus-axion potential
with the double exponential function. Although the axion has a period of small
value, this potential can have a flat region because its derivatives are
exponentially suppressed by non-perturbative effects. From the view point of
the cosmic inflation, such potential is interesting. In this paper, we
numerically study the possibilities for realizing the cosmic inflation. We also
study their spectral index and other cosmological observables, numerically.Comment: 13 pages, 2 figure
Two-loop Renormalization Factors of Dimension-six Proton Decay Operators in the Supersymmetric Standard Models
The renormalization factors of the dimension-six effective operators for
proton decay are evaluated at two-loop level in the supersymmetric grand
unified theories. For this purpose, we use the previous results in which the
quantum corrections to the effective Kahler potential are evaluated at
two-loop level. Numerical values for the factors are presented in the case of
the minimal supersymmetric SU(5) grand unified model. We also derive a simple
formula for the one-loop renormalization factors for any higher-dimensional
operators in the Kahler potential, assuming that they are induced by the gauge
interactions.Comment: 11 pages. Version accepted for publication in Phys. Lett.
Nucleon Electric Dipole Moments in High-Scale Supersymmetric Models
The electric dipole moments (EDMs) of electron and nucleons are promising
probes of the new physics. In generic high-scale supersymmetric (SUSY)
scenarios such as models based on mixture of the anomaly and gauge mediations,
gluino has an additional contribution to the nucleon EDMs. In this paper, we
studied the effect of the -violating gluon Weinberg operator induced by the
gluino chromoelectric dipole moment in the high-scale SUSY scenarios, and we
evaluated the nucleon and electron EDMs in the scenarios. We found that in the
generic high-scale SUSY models, the nucleon EDMs may receive the sizable
contribution from the Weinberg operator. Thus, it is important to compare the
nucleon EDMs with the electron one in order to discriminate among the
high-scale SUSY models.Comment: 22 pages, 8 figures, Version accepted for publication in JHE
F-term Moduli Stabilization and Uplifting
We study K\"ahler moduli stabilization in IIB superstring theory. We propose
a new moduli stabilization mechanism by the supersymmetry-braking chiral
superfield which is coupled to K\"ahler moduli in K\"ahler potential. We also
study uplifting of the Large Volume Scenario (LVS) by it. In both cases, the
form of superpotential is crucial for moduli stabilization. We confirm that our
uplifting mechanism does not destabilize the vacuum of the LVS drastically.Comment: 22 pages, 2 figure
Detection and visualization of encoded local features as anatomical predictors in cross-sectional images of Lauraceae
This paper describes computer vision-based quantitative microscopy and its application toward better understanding species specificity. An image dataset of the Lauraceae family that consists of nine species across six genera was investigated, and structural features were quantified using encoded local features implemented in a bag-of-features framework. Of the algorithms used for feature detection, the scale-invariant feature transform (SIFT) achieved the best performance in species discrimination. In the bag-of-features framework with the SIFT features, each image is represented by a histogram of codewords. The codewords were further analyzed by mapping them to each image to visualize the corresponding anatomical elements. From this analysis, we were able to classify and quantify the modes of aggregation of different combinations of cell elements based on clustered codewords. An analysis of the term frequency–inverse document frequency weights revealed that blob-based codewords are generally shared by all species, whereas corner-based codewords are more species specific
Effective Interaction of Electroweak-Interacting Dark Matter with Higgs Boson and Its Phenomenology
We study phenomenology of electroweak-interacting fermionic dark matter (DM)
with a mass of GeV. Constructing the effective Lagrangian
that describes the interactions between the Higgs boson and the SU(2)
isospin multiplet fermion, we evaluate the electric dipole moment (EDM) of
electron, the signal strength of Higgs boson decay to two photons and the
spin-independent elastic-scattering cross section with proton. As
representative cases, we consider the SU(2) triplet fermions with
zero/nonzero hypercharges and SU(2) doublet fermion. It is found that the
electron EDM gives stringent constraints on those model parameter spaces. In
the cases of the triplet fermion with zero hypercharge and the doublet fermion,
the Higgs signal strength does not deviate from the standard model prediction
by more than a few % once the current DM direct detection constraint is taken
into account, even if the CP violation is suppressed. On the contrary,
- % deviation may occur in the case of the triplet fermion
with nonzero hypercharge. Our representative scenarios may be tested by the
future experiments.Comment: 13 pages, 5 figures. Version accepted for publication in Phys. Lett.
Examination of Cinnamomum camphora interlocked grain adopting X-ray computed tomography combined with particle image velocimetry
Trees develop wood grain more or less parallel to the tree axis as they grow laterally. However, many tree species also develop interlocked grain that is expressed as a change in the wood grain orientation, periodically switching between left- and right-handed spirals over the years. Wood grain information is critical to determining the wood quality and is an important record of cellular events in a cambium. This study examined the wood grain of axial xylem cells in the semi-ring porous hardwood Cinnamomum camphora by first visualizing the three-dimensional structure using a conventional X-ray computed tomography instrument producing tomography images. We propose the use of particle image velocimetry (PIV) and the two-dimensional fast Fourier transform (2D-FFT) to analyze computed tomography images in obtaining grain angle (δ) information from the vessel deviation. We found undulation on the radial variation of the grain angle (δ) that indicates periodical changes in the wood grain orientation as left- and right-handed spirals ranging from − 25° to 16° and − 22° to 18° using the 2D-FFT and PIV, respectively. Furthermore, despite the major orientation of vessels inclining in the tangential direction, the PIV result revealed a minor deviation with vessels inclining in various orientations along the tree radius
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