5,822 research outputs found
Mass Matrices in E6 Unification
We study a supersymmetric E6 grand unified model in which the SU(5) 5^*
components are twisted in the third generation 27. Supplementing the adjoint
Higgs field to a model analyzed previously, we calculate the mass matrices for
the up and down quarks and charged leptons. Although the number of free
parameters is less than that of observables, an overall fitting to the observed
masses and mixing angles is shown to be possible. Most notably, we find two
novel, parameter-independent relations between the lepton 2-3 mixing angle and
the quark masses and CKM mixing angles that are in good agreement with the
large lepton mixing recently observed.Comment: 33 pages, 5 figures, typos correcte
Phenomenology of Neutrino Mass Matrix
The search for possible mixing patterns of charged leptons and neutrinos is
important to get clues of the origin of nearly maximal mixings, since there are
some preferred bases of the lepton mass matrices given by underlying theories.
We systematically examine the mixing patterns which could lead to large lepton
mixing angles. We find out 37 mixing patterns are consistent with experimental
data if taking into account phase factors in the mixing matrices. Only 6
patterns of them can explain the observed data without any tuning of
parameters, while the others need particular choices for phase values.Comment: revised reference
Intermediate left-right gauge symmetry, unification of couplings and fermion masses in SUSY
If left-right gauge theory occurs as an intermediate symmetry in a GUT then,
apart from other advantages, it is possible to obtain the see-saw scale
necessary to understand small neutrino masses with Majorana coupling of order
unity. Barring threshold or non-renormalizable gravitational effects, or
assumed presence of additional light scalar particles of unprescribed origin,
all other attempts to achieve manifest one-loop gauge coupling unification in
SUSY SO(10) with left-right intermediate symmetry have not been successful so
far. Attributing this failure to lack of flavor symmetry in the GUT, we show
how the spontaneous symmetry breaking of leads to such
intermediate scale extending over a wide range, GeV
to GeV. All the charged fermion masses are fitted at the see-saw
scale, GeV which is obtained with
Majorana coupling . Using a constrained parametrization in which
CP-violation originates only from quark sector, besides other predictions made
in the neutrino sector, the reactor mixing angle is found to be which is in the range accessible to ongoing and
planned experiments. The leptonic Dirac phase turns out to be radians with Jarlskog invariant .Comment: Minor clarification and few references added to match the published
versio
Activation gaps for the fractional quantum Hall effect: realistic treatment of transverse thickness
The activation gaps for fractional quantum Hall states at filling fractions
are computed for heterojunction, square quantum well, as well as
parabolic quantum well geometries, using an interaction potential calculated
from a self-consistent electronic structure calculation in the local density
approximation. The finite thickness is estimated to make 30% correction
to the gap in the heterojunction geometry for typical parameters, which
accounts for roughly half of the discrepancy between the experiment and
theoretical gaps computed for a pure two dimensional system. Certain model
interactions are also considered. It is found that the activation energies
behave qualitatively differently depending on whether the interaction is of
longer or shorter range than the Coulomb interaction; there are indications
that fractional Hall states close to the Fermi sea are destabilized for the
latter.Comment: 32 pages, 13 figure
Density Matrix Renormalization Group and the Nuclear Shell Model
We describe the use of the Density Matrix Renormalization Group method as a
means of approximately solving large-scale nuclear shell-model problems. We
focus on an angular-momentum-conserving variant of the method and report test
results for the nucleus . The calculation is able to reproduce both
the ground state energy and the energy of the first excited state, by
diagonalizing matrices much smaller than those of the full shell model.Comment: 7 pages, 3 figures; To appears in Phys. Rev.
Gap Condition and Self-Dualized Super Yang-Mills Theory for ADE Gauge Group on K3
We try to determine the partition function of super Yang-Mills
theoy for ADE gauge group on K3 by self-dualizing our previous ADE partition
function. The resulting partition function satisfies gap condition.Comment: 17 page
A comparison of ultraviolet sensitivities in universal, nonuniversal, and split extra dimensional models
We discuss the origin of ultraviolet sensitivity in extra dimensional
theories, and compare and contrast the cutoff dependences in universal,
nonuniversal and split five dimensional models. While the gauge bosons and
scalars are in the five dimensional bulk in all scenarios, the locations of the
fermions are different in different cases. In the universal model all fermions
can travel in the bulk, in the nonuniversal case they are all confined at the
brane, while in the split scenario some are in the bulk and some are in the
brane. A possible cure from such divergences is also discussed.Comment: 9 pages, Latex, no figure, v2: further clarifications and references
added, accepted for publication in Phys. Rev.
Evolution of the human fear-circuitry and acute sociogenic pseudoneurological symptoms: The Neolithic balanced-polymorphism hypothesis
In light of the increasing threat of large-scale massacres such as terrorism against non-combatants (civilians), more attention is warranted not only to posttraumatic stress disorder (PTSD) but also to acute sociogenic pseudoneurological ("conversion") symptoms, especially epidemic sociogenic symptoms. We posit that conversion disorders are etiologically related to specific evolutionary pressures (inescapable threats to life) in the late stage of the human environment of evolutionary adaptedness (EEA). Bracha et al. have recently argued that from the neuroevolutionary perspective, medically unexplained efferent vasovagal syncope and medically unexplained craniofacial musculoskeletal pain in young otherwise healthy individuals, may be taxonomized as stress and fear-circuitry disorders. In the present article, we extend neuroevolutionary perspectives to acute pseudoneurological sociogenic ("conversive") symptoms: psychogenic non-epileptic attacks ("pseudoseizures"), epidemic sociogenic disorders (DSM-IV-TR Epidemic "Hysteria"), conversive motor deficits (pseudo-paralysis and pseudo-cerebellar symptoms), and psychogenic blindness. We hypothesize that these perplexing pseudoneurological stress-triggered symptoms, which constitute psychopathology in extant humans, are traceable to allele-variant polymorphisms which spread during the Neolithic EEA. During Neolithic warfare, conversive symptoms may have increased the survival odds for some non-combatants by visually (i.e., "non-verbally") signaling to predatory conspecifics that one does not present a danger. This is consistent with the age and sex pattern of conversive disorders. Testable and falsifiable predictions are presented; e.g., at the genome-transcriptome interface, one of the major oligogenic loci involved in conversive spectrum disorders may carry a developmentally sensitive allele in a stable polymorphism (balanced polymorphism) in which the gene expression mechanism is gradually suppressed by pleiotropic androgens especially dehydroxyepiandrosterone sulfate (DHEA-S). Taxonomic implications for the much-needed rapprochement between the forthcoming Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-V) and the International Classification of Diseases (ICD) are discussed
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