669 research outputs found
<Session 3: Biomedical Technology>Bio-Signal Electrodes Having Electro-Chemical Power Generation Capability Aimed for Operating Power of Intra-Corporeal Capsule-Telemeter Transmitter
19–22 May 2022 Kyoto, JapanPlease provide a brief abstract here of approximately 200 words. To distinguish it from the main text, please place the abstract in cursive text - font size 10, Times New Roman
Abundance of Cosmological Relics in Low-Temperature Scenarios
We investigate the relic density n_\chi of non-relativistic long-lived or
stable particles \chi in cosmological scenarios in which the temperature T is
too low for \chi to achieve full chemical equilibrium. The case with a heavier
particle decaying into \chi is also investigated. We derive approximate
solutions for n_\chi(T) which accurately reproduce numerical results when full
thermal equilibrium is not achieved. If full equilibrium is reached, our ansatz
no longer reproduces the correct temperature dependence of the \chi number
density. However, it does give the correct final relic density, to an accuracy
of about 3% or better, for all cross sections and initial temperatures.Comment: 26 pages, 8 figures, comments added, to appear in Phys. Rev.
Update on Fermion Mass Models with an Anomalous Horizontal U(1) Symmetry
We reconsider models of fermion masses and mixings based on a gauge anomalous
horizontal U(1) symmetry. In the simplest model with a single flavon field and
horizontal charges of the same sign for all Standard Model fields, only very
few charge assignements are allowed when all experimental data, including
neutrino oscillation data, is taken into account. We show that a precise
description of the observed fermion masses and mixing angles can easily be
obtained by generating sets of the order one parameters left unconstrained by
the U(1) symmetry. The corresponding Yukawa matrices show several interesting
features which may be important for flavour changing neutral currents and CP
violation effects in supersymmetric models.Comment: 23 pages, 8 figure
Twisted Split Fermions
The observed flavor structure of the standard model arises naturally in
"split fermion" models which localize fermions at different places in an extra
dimension. It has, until now, been assumed that the bulk masses for such
fermions can be chosen to be flavor diagonal simultaneously at every point in
the extra dimension, with all the flavor violation coming from the Yukawa
couplings to the Higgs. We consider the more natural possibility in which the
bulk masses cannot be simultaneously diagonalized, that is, that they are
twisted in flavor space. We show that, in general, this does not disturb the
natural generation of hierarchies in the flavor parameters. Moreover, it is
conceivable that all the flavor mixing and CP-violation in the standard model
may come only from twisting, with the five-dimensional Yukawa couplings taken
to be universal.Comment: 15 pages, 1 figur
Gauge Coupling Unification in GUT with Anomalous U(1) Symmetry
We show that in the framework of grand unified theory (GUT) with anomalous
gauge symmetry, the success of the gauge coupling unification in the
minimal SU(5) GUT is naturally explained, even if the mass spectrum of
superheavy fields does not respect SU(5) symmetry. Because the unification
scale for most realizations of the theory becomes smaller than the usual GUT
scale, it suggests that the present level of experiments is close to that
sufficient to observe proton decay via dimension 6 operators, .Comment: 4 pages, RevTeX, to appear in Phys.Rev.Let
Democratic (S)fermions and Lepton Flavor Violation
The democratic approach to account for fermion masses and mixing is known to
be successful not only in the quark sector but also in the lepton sector. Here
we extend this ansatz to supersymmetric standard models, in which the K\"ahler
potential obeys underlying S_3 flavor symmetries. The requirement of neutrino
bi-large mixing angles constrains the form of the K\"ahler potential for
left-handed lepton multiplets. We find that right-handed sleptons can have
non-degenerate masses and flavor mixing, while left-handed sleptons are argued
to have universal and hence flavor-blind masses. This mass pattern is testable
in future collider experiments when superparticle masses will be measured
precisely. Lepton flavor violation arises in this scenario. In particular, \mu
\to e \gamma is expected to be observed in a planning future experiment if
supersymmetry breaking scale is close to the weak scale.Comment: 22 pages, 2 figure
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