346 research outputs found
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
Study of lepton flavor violation in flavor symmetric models for lepton sector
Flavor symmetric model is one of the attractive Beyond Standard Models (BSMs)
to reveal the flavor structure of the Standard Model (SM). A lot of efforts
have been put into the model building and we find many kinds of flavor
symmetries and setups are able to explain the observed fermion mass matrices.
In this paper, we look for common predictions of physical observables among the
ones in flavor symmetric models, and try to understand how to test flavor
symmetry in experiments. Especially, we focus on the BSMs for leptons with
extra Higgs doublets charged under flavor symmetry. In many flavor
models for leptons, remnant symmetry is partially respected after the flavor
symmetry breaking, and it controls well the Flavor Changing Neutral Currents
(FCNCs) and suggests some crucial predictions against the flavor changing
process, although the remnant symmetry is not respected in the full lagrangian.
In fact, we see that and processes are the most important in the
flavor models that the extra Higgs doublets belong to triplet representation of
flavor symmetry. For instance, the stringent constraint from the process could be evaded according to the partial remnant symmetry. We
also investigate the breaking effect of the remnant symmetry mediated by the
Higgs scalars, and investigate the constraints from the flavor physics: the
flavor violating and decays, the electric dipole moments, and the
muon anomalous magnetic moment. We also discuss the correlation between FCNCs
and nonzero , and point out the physical observables in the
charged lepton sector to test the BSMs for the neutrino mixing.Comment: 29 pages, 11 figure
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.
Effects of Microalloying on the Impact Toughness of Ultrahigh-Strength TRIP-Aided Martensitic Steels
The effects of the addition of Cr, Mo, and/or Ni on the Charpy impact toughness of a 0.2 pct C-1.5 pct Si-1.5 pct Mn-0.05 pct Nb transformation-induced plasticity (TRIP)-aided steel with a lath-martensite structure matrix (i.e., a TRIP-aided martensitic steel or TM steel) were investigated with the aim of using the steel in automotive applications. In addition, the relationship between the toughness of the various alloyed steels and their metallurgical characteristics was determined. When Cr, Cr-Mo, or Cr-Mo-Ni was added to the base steel, the TM steel exhibited a high upper-shelf Charpy impact absorbed value that ranged from 100 to 120 J/cm2 and a low ductile–brittle fracture appearance transition temperature that ranged from 123 K to 143 K (−150 °C to −130 °C), while also exhibiting a tensile strength of about 1.5 GPa. This impact toughness of the alloyed steels was far superior to that of conventional martensitic steel and was caused by the presence of (i) a softened wide lath-martensite matrix, which contained only a small amount of carbide and hence had a lower carbon concentration, (ii) a large amount of finely dispersed martensite-retained austenite complex phase, and (iii) a metastable retained austenite phase of 2 to 4 vol pct in the complex phase, which led to plastic relaxation via strain-induced transformation and played an important role in the suppression of the initiation and propagation of voids and/or cleavage cracks.ArticleMETALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE. 44A(11):5006-5017 (2013)journal articl
Longitudinal relationships between cardiovascular events, risk factors, and time-dependent sleep duration
Background: Although many studies have evaluated the relationships between sleep duration and cardiovascular (CV) events/risk factors, longitudinal associations with time-dependent sleep duration have not been adequately assessed.
Methods: A retrospective, longitudinal study was conducted involving individuals aged 20 years or older that received annual health check-ups at St. Luke’s International Hospital from 2005 to 2010. Data collection included self-reported demographic, clinical and health habit information (including sleep duration; < 6, 6–7, 7–8, ≥ 8 h), baseline examinations, and laboratory measures for each year. We conducted mixed effects analyses to examine the associations between non-fatal CV events, risk factors, and time-dependent sleep duration longitudinally.
Results: Of the total of 31,830 participants enrolled, 70.1% of participants changed their sleep duration, and 365 participants experienced CV events during follow-up periods. Compared to those reporting 7–8 h of sleep, those reporting less than 6 h of sleep were significantly more likely to experience non-fatal CV events (odds ratio [OR] 1.78; 95% confidence interval [CI] 1.03–3.07; p = 0.04), but other groups were not (OR 1.12; 95% CI 0.70–1.77; p = 0.64 for 6–7 h and OR 1.22; 95% CI 0.68–2.23; p = 0.50 for ≥ 8 h). The shortest sleep duration was associated with a higher likelihood of obesity/overweight status (OR 1.49; 95% CI 1.32–1.69; p < 0.01).
Conclusions: Individuals reporting less than 6 h of sleep were significantly more likely to have non-fatal CV events than those reporting 7–8 h of sleep. For the risk factors, short sleep duration was associated with obesity/overweight status
Revisiting Discrete Dark Matter Model:\theta_{13}\neq0 and \nu_{R} Dark Matter
We revisit the discrete dark matter model with flavor symmetry
originally introduced by M.Hirsch {\it et.al}. We show that radiative
corrections can lead to non-zero and non-zero mass for the
lightest neutrino. We find an interesting relation among neutrino mixing
parameters and it indicates the sizable deviation of from the maximal
angle and the degenerate mass spectrum for neutrinos. Also we
study the possibilities that the right-handed neutrino is a dark matter
candidate. Assuming the thermal freeze-out explains observed dark matter
abundance, TeV-scale right-handed neutrino and flavored scalar bosons are
required. In such a case, flavor symmetry plays an important role for the
suppression of lepton flavor violating processes as well as for the stability
of dark matter. We show that this scenario can be viable against currently
existing constraints from collider, low energy experiments and cosmological
observations.Comment: The wrong estimations in Eq(4.9) and Fig.14 in the published version
of this paper are corrected. As the result, the prefered mass range for
bosons are lowered. Some comments on constraints from rare lepton
decays and SM precision test adde
Long-range order and low-energy magnetic excitations in CeRu2Al10
The nature of the unconventional ordered phase occurring in CeRu2Al10 below
T0 = 27 K was investigated by neutron scattering. Powder diffraction patterns
show clear superstructure peaks corresponding to forbidden (h + k)-odd
reflections of the Cmcm space group. Inelastic neutron scattering experiments
further reveal a pronounced magnetic excitation developing in the ordered phase
at an energy of 8 meV.Comment: 5 pages; 4 figure
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