51 research outputs found
Thermal leptogenesis in a supersymmetric neutrinophilic Higgs model
We investigate thermal leptogenesis in a supersymmetric neutrinophilic Higgs
model by taking phenomenological constraints into account, where, in addition
to the minimal supersymmetric standard model, we introduce an extra Higgs field
with a tiny vacuum expectation value (VEV) which generates neutrino masses.
Thanks to this tiny VEV of the neutrinophilic Higgs, our model allows to reduce
the mass of the lightest right-handed (s)neutrino to be GeV as
keeping sufficiently large CP asymmetry in its decay. Therefore, the reheating
temperature after inflation is not necessarily high, hence this scenario is
free from gravitino problem.Comment: 5 pages, 1 figur
Inner centromere formation requires hMis14, a trident kinetochore protein that specifically recruits HP1 to human chromosomes
hMis14 and HP1 depend on each other to localize to the kinetochore and inner centromere, respectively
Thermal leptogenesis in brane world cosmology
The thermal leptogenesis in brane world cosmology is studied. In brane world
cosmology, the expansion law is modified from the four-dimensional standard
cosmological one at high temperature regime in the early universe. As a result,
the well-known upper bound on the lightest light neutrino mass induced by the
condition for the out-of-equilibrium decay of the lightest heavy neutrino,
eV, can be moderated to be in the case of with the
lightest heavy neutrino mass () and the ``transition temperature''
(), at which the modified expansion law in brane world cosmology is
smoothly connecting with the standard one. This implies that the degenerate
mass spectrum of the light neutrinos can be consistent with the thermal
leptogenesis scenario. Furthermore, as recently pointed out, the gravitino
problem in supersymmetric case can be solved if the transition temperature is
low enough GeV. Therefore, even in the supersymmetric
case, thermal leptogenesis scenario can be successfully realized in brane world
cosmology.Comment: 9 pages, final versio
Mis16 and Mis18 Are Required for CENP-A Loading and Histone Deacetylation at Centromeres
AbstractCentromeres contain specialized chromatin that includes the centromere-specific histone H3 variant, spCENP-A/Cnp1. Here we report identification of five fission yeast centromere proteins, Mis14–18. Mis14 is recruited to kinetochores independently of CENP-A, and, conversely, CENP-A does not require Mis14 to associate with centromeres. In contrast, Mis15, Mis16 (strong similarity with human RbAp48 and RbAp46), Mis17, and Mis18 are all part of the CENP-A recruitment pathway. Mis15 and Mis17 form an evolutionarily conserved complex that also includes Mis6. Mis16 and Mis18 form a complex and maintain the deacetylated state of histones specifically in the central core of centromeres. Mis16 and Mis18 are the most upstream factors in kinetochore assembly as they can associate with kinetochores in all kinetochore mutants except for mis18 and mis16, respectively. RNAi knockdown in human cells shows that Mis16 function is conserved as RbAp48 and RbAp46 are both required for localization of human CENP-A
Mass Measurement of the Decaying Bino at the LHC
In some class of supersymmetric (SUSY) models, the neutral Wino becomes the
lightest superparticle and the Bino decays into the Wino and standard-model
particles. In such models, we show that the measurement of the Bino mass is
possible if the short charged tracks (with the length of O(10 cm)) can be
identified as a signal of the charged-Wino production. We pay particular
attention to the anomaly-mediated SUSY-breaking (AMSB) model with a generic
form of K\"ahler potential, in which only the gauginos are kinematically
accessible superparticles to the LHC, and discuss the implication of the Bino
mass measurement for the test of the AMSB model.Comment: 13 pages, 3 figures, 1 tabl
A Model of TeV Scale Physics for Neutrino Mass, Dark Matter and Baryon Asymmetry and its Phenomenology
We discuss some details for the model proposed in Ref. \cite{aks-prl}, in
which neutrino oscillation, dark matter, and baryon asymmetry of the Universe
can be simultaneously explained by the TeV-scale physics without introducing
very high mass scales. An exact discrete symmetry is introduced, under
which new particle contents (a real singlet scalar field, a pair of charged
singlet scalar fields and TeV-scale right-handed neutrinos) are assigned to
have odd quantum number, whereas ordinary gauge fields, quarks and leptons, and
two Higgs doublets are even. Tiny neutrino masses are generated at the three
loop level due to the exact symmetry, by which stability of the dark
matter candidate is also guaranteed. The extra Higgs doublet is required not
only for the tiny neutrino masses but also for successful electroweak
baryogenesis. We discuss phenomenological properties of the model, and find
that there are successful scenarios in which above three problems are solved
simultaneously under the constraint from current experimental data. We then
discuss predictions in such scenarios at ongoing and future experiments. It
turns out that the model provides discriminative predictions especially in
Higgs physics and dark matter physics, so that it is testable in near future.Comment: Version accepted for publication in Physical Review D, 43 pages, 23
figures. Revised Figs.13 and 14, minor errors and typos corrected, added
footnote
Neutrino mass, Dark Matter and Baryon Asymmetry via TeV-Scale Physics without Fine-Tuning
We propose an extended version of the standard model, in which neutrino
oscillation, dark matter, and baryon asymmetry of the Universe can be
simultaneously explained by the TeV-scale physics without assuming unnatural
hierarchy among the mass scales. Tiny neutrino masses are generated at the
three loop level due to the exact symmetry, by which stability of the
dark matter candidate is guaranteed. The extra Higgs doublet is required not
only for the tiny neutrino masses but also for successful electroweak
baryogenesis. The model provides discriminative predictions especially in Higgs
phenomenology, so that it is testable at current and future collider
experiments.Comment: 4 pages including 3 figures; version with revised figure
Originally Asymmetric Dark Matter
We propose a scenario with a fermion dark matter, where the dark matter
particle used to be the Dirac fermion, but it takes the form of the Majorana
fermion at a late time. The relic number density of the dark matter is
determined by the dark matter asymmetry generated through the same mechanism as
leptogenesis when the dark matter was the Dirac fermion. After efficient dark
matter annihilation processes have frozen out, a phase transition of a scalar
field takes place and generates Majorana mass terms to turn the dark matter
particle into the Majorana fermion. In order to address this scenario in
detail, we propose two simple models. The first one is based on the Standard
Model (SM) gauge group and the dark matter originates the doublet
Dirac fermion, analogous to the Higgsino-like neutralino in supersymmetric
models. We estimate the spin-independent/dependent elastic scattering cross
sections of this late-time Majorana dark matter with a proton and find the
possibility to discover it by the direct and/or indirect dark matter search
experiments in the near future. The second model is based on the gauged
extension of the SM, where the dark matter is a SM singlet. Although this model
is similar to the so-called Higgs portal dark matter scenario, the
spin-independent elastic scattering cross section can be large enough to detect
this dark matter in future experiments.Comment: 24 pages. Final journal versio
Sterile neutrino dark matter in extension of the standard model and galactic 511 keV line
Sterile right-handed neutrinos can be naturally embedded in a low scale
gauged extension of the standard model. We show that, within a low
reheating scenario, such a neutrino is an interesting candidate for dark
matter. We emphasize that if the neutrino mass is of order of MeV, then it
accounts for the measured dark matter relic density and also accommodates the
observed flux of 511 keV photons from the galactic bulge.Comment: 10 pages, 1 figure, references added, final version appeared in JCA
Evaluation of oral immunotherapy efficacy and safety by maintenance dose dependency: A multicenter randomized study
Background
Generally, oral immunotherapy (OIT) aims for daily administration. Recently, the efficacy of treatment with OIT at a low dose has been reported. However, the optimal dose and the evaluation of dose-dependent OIT outcome have not been described.
Methods
A multicenter, parallel, open-labeled, prospective, non-placebo controlled, randomized study enrolled 101 Japanese patients for treatment with OIT. We hypothesized that target dose OIT would induce short-term unresponsiveness (StU) earlier than reduced dose OIT. StU was defined as no response to 6200 mg whole egg, 3400 mg milk, and 2600 mg wheat protein, as evaluated by oral food challenge after 2-week ingestion cessation. To compare the two doses of OIT efficacy, the maximum ingestion doses during the maintenance phase of OIT were divided into 100%-dose or 25%-dose groups against their target StU dose, respectively. A total of 51 patients were assigned to the 100%-dose group [hen's egg (HE) = 26, cow's milk (CM) = 13, wheat = 12] and 50 to the 25%-dose group (HE = 25, CM = 13, wheat = 12). Primary outcome was established by comparing StU at 1 year. Secondary outcome was StU at 2 years and established by comparing allergic symptoms and immunological changes.
Results
The year 1 StU rates (%) for the 100%- and 25%-dose groups were 26.9 vs. 20.0 (HE), 7.7 vs. 15.4 (CM), and 50.0 vs. 16.7 (wheat), respectively. The year 2 StU rates were 30.8 vs. 36.0 (HE), 7.7 vs. 23.1 (CM), and 58.3 vs. 58.3 (wheat), respectively. There were no statistically significant differences in StU between years 1 and 2. The total allergic symptom rate in the 25%-dose group was lower than that in the 100%-dose group for egg, milk, and wheat. Antigen-specific IgE levels for egg-white, milk, and wheat decreased at 12 months.
Conclusions
Reduced maintenance dose of egg OIT showed similar therapeutic efficacy to the target dose. However, we were not able to clearly demonstrate the efficacy, particularly for milk and wheat. Reducing the maintenance dose for eggs, milk, and wheat may effectively lower the symptoms associated with their consumption compared to the target OIT dose. Furthermore, aggressive reduction of the maintenance dose might be important for milk and wheat, compared to the 25%-dose OIT
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