7,612 research outputs found
Mediation of Supersymmetry Breaking via Anti-Generation Fields
In the context of the weakly coupled heterotic string, we propose a new model
of mediating supersymmetry breaking. The breakdown of supersymmetry in the
hidden sector is transmitted to anti-generation fields via gravitational
interactions. Subsequent transmission of the breaking to the MSSM sector occurs
via gauge interactions. It is shown that the mass spectra of superparticles are
phenomenologically viable.Comment: 8pages, LaTeX, 1 figure, final version to appear in Prog. Theor.
Phys. Vol.103, No.6 (2000
Quark Mixings in and Suppression of
The quark mixing matrix is studied in depth on the basis of
superstring inspired model with global flavor symmetries.
The sizable mixings between right-handed down-type quark and colored
Higgs field potentially occur but no such mixings in up-type quark
sector. In the model the hierarchical pattern of is understood
systematically. It is shown that due to large - mixings is
naturally suppressed compared to . It is pointed out that the observed
suppression of is in favor of the presence of gauge symmetry
but not in accord with generic SU(5) GUT.Comment: 10pages with no figure, Latex fil
A class of Bell diagonal states and entanglement witnesses
We analyze special class of bipartite states - so called Bell diagonal
states. In particular we provide new examples of bound entangled Bell diagonal
states and construct the class of entanglement witnesses diagonal in the magic
basis.Comment: 17 page
Adhesive for aluminum withstands cryogenic temperatures
Polyurethane adhesive mixed to various proportions with milled glass fibers match the thermal characteristics of 2014-T6 aluminum at cryogenic temperatures
Fermion Masses and Mixings in a String Inspired Model
In the context of Calabi-Yau string models we explore the origin of
characteristic pattern of quark-lepton masses and the CKM matrix. The discrete
-symmetry is introduced and the is assigned to the
-parity. The gauge symmetry at the string scale, , is
broken into the standard model gauge group at a very large intermediate energy
scale. At energies below the intermediate scale down-type quarks and also
leptons are mixed with unobserved heavy states, respectively. On the other
hand, there are no such mixings for up-type quarks. Due to the large mixings
between light states and heavy ones we can derive phenomenologically viable
fermion mass hierarchies and the CKM matrix. Mass spectra for
intermediate-scale matter beyond the MSSM are also determined. Within this
framework proton lifetime is long enough to be consistent with experimental
data. As for the string scale unification of gauge couplings, however,
consistent solutions are not yet found.Comment: 49 pages, 1 figure, Latex Revised version includes discussion on FCNC
problems. Final version to appear in Prog. Theor. Phys. Vol.96 No.
OAO/ISLE Near-IR Spectroscopy of IRAS Galaxies
We present the results of the near-infrared (IR) spectroscopy of nine IRAS
galaxies (NGC 1266, NGC 1320, NGC 2633, NGC 2903, NGC 3034, Mrk 33, NGC 7331,
NGC 7625, NGC 7714) with the ISLE imager and spectrograph mounted on the
Okayama Astrophysical Observatory 1.88 m telescope. [Fe II] 1.257 um and Pa
beta emission lines were observed for the whole sample while H2 2.121 um and Br
gamma lines were additionally obtained for two sources, whose flux ratios are
used as a diagnostic tool of dominant energy sources of the galaxies. We find
that the nucleus of NGC 1266 is most likely a low ionization nuclear
emission-line region (LINER), while NGC 2633 and NGC 2903 possibly harbor
active galactic nuclei (AGNs). No AGN or LINER signal is found for other
objects. In addition, we find the spectral features which is indicative of some
unusual phenomena occurring in the galaxies, such as the large [Fe II] line
widths compared to the local escape velocity in NGC 1266. The present work
shows the potential ability of the ISLE to shed new light on the nature of
infrared galaxies, either through a statistical survey of galaxies or an
exploration of spectral features found in individual objects.Comment: Accepted for publication in PAS
An investigation of star formation and dust attenuation in major mergers using ultraviolet and infrared data
Merger processes play an important role in galaxy formation and evolution. To
study the influence of merger processes on the evolution of dust properties and
cosmic star formation rate, we investigate a local sample of major merger
galaxies and a control sample of isolated galaxies using GALEX ultraviolet (UV)
and Spitzer infrared (IR) images. Through a statistical study, we find that
dust attenuation in merger galaxies is enhanced with respect to isolated
galaxies. We find this enhancement is contributed mainly by spiral galaxies in
spiral-spiral (S-S) pairs, and increases with the increasing stellar mass of a
galaxy. Combining the IR and UV parts of star formation rates (SFRs), we then
calculated the total SFRs and specific star formation rates (SSFRs). We find
the SSFRs to be enhanced in merger galaxies. This enhancement depends on galaxy
stellar mass and the companion's morphology, but depends little on whether the
galaxy is a primary or secondary component or on the separation between two
components. These results are consistent with a previous study based only on IR
images. In addition, we investigate the nuclear contributions to SFRs. SFRs in
paired galaxies are more concentrated in the central part of the galaxies than
in isolate galaxies. Our studies of dust attenuation show that the nuclear
parts of pairs most resemble ULIRGs. Including UV data in the present work not
only provides reliable information on dust attenuation, but also refines
analyses of SFRs.Comment: 21 pages, 21 figure
How Can We Obtain a Large Majorana-Mass in Calabi-Yau Models ?
In a certain type of Calabi-Yau superstring models it is clarified that the
symmetry breaking occurs by stages at two large intermediate energy scales and
that two large intermediate scales induce large Majorana-masses of right-handed
neutrinos. Peculiar structure of the effective nonrenormalizable interactions
is crucial in the models. In this scheme Majorana-masses possibly amount to
O(10^{9 \sim 10}\gev) and see-saw mechanism is at work for neutrinos. Based
on this scheme we propose a viable model which explains the smallness of masses
for three kind of neutrinos .
Special forms of the nonrenormalizable interactions can be understood as a
consequence of an appropriate discrete symmetry of the compactified manifold.Comment: 30-pages + 6-figures, LaTeX, Preprint DPNU-94-02, AUE-01-9
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