2,209 research outputs found
Atomki anomaly and the Secluded Dark Sector
The Atomiki anomaly can be interpreted as a new light vector boson. If such a
new particle exists, it could be a mediator between the Standard Model sector
and the dark sector including the dark matter. We discussed some simple
effective models with these particles. In the models, the secluded dark matter
models are good candidates to satisfy the thermal relic abundance. In
particular, we found that the dark matter self-interaction can be large enough
to solve the small scale structure puzzles if the dark matter is a fermion.Comment: 5 pages, 4 figures, etc.; contribution to the proceedings of Joint
Conference of ICGAC-XIII and IK15, Seoul, 3-7 July 2017; based on 1609.0160
Unitarity Bounds on Dark Matter Effective Interactions at LHC
The perturbative unitarity bound is studied in the monojet process at LHC.
The production of the dark matter is described by the low-energy effective
theory. The analysis of the dark matter signal is not validated, if the
unitarity condition is violated. It is shown that the current LHC analysis the
effective theory breaks down, at least, when the dark matter is lighter than
O(100) GeV. Future prospects for = 14 TeV are also discussed. The
result is independent of physics in high energy scales.Comment: 14 pages, 12 figures; v2: footnotes and references are added; figures
are slightly change
Current Status of Autoimmune Hepatitis in Japan
Autoimmune hepatitis (AIH) is a chronic and progressive disease characterized by histological interface hepatitis, hypergammaglobulinemia, and circulating autoantibodies. Multiple factors, including molecular mimicry, a genetic background including major histocompatibility complex class II, and defective function of regulatory T-cells, are involved in the pathogenesis. The diagnosis is made based on the scoring system of the International Autoimmune Hepatitis Group, the sensitivity and specificity of which are90%, respectively. AIH is classified into 3 sub-types based on the profiles of circulating autoantibodies: anti-nuclear antibody and/or smooth muscle antibody-positive (type 1), anti-liver-kidney microsomal antibody-positive (type 2), and anti-soluble liver antigen/liver-pancreas antigen antibody- positive (type 3). Recently, however, the number of atypical cases lacking the usual features has increased-for example, patients with acute-onset or fulminant-type AIH, autoantibody-negative patients, male patients, and patients with bile duct injury-and thus the clinical features of AIH have been diversified. AIH is responsive to immunosuppressive treatment in most cases; however, relapse occurs in more than 80% of patients within 1 year after immunosuppressive treatment withdrawal. The 10-year survival rate and the 10-year hepatocellular carcinoma-free rate are90%, respectively, indicating that some patients reach liver failure or develop hepatocellular carcinoma. To improve the prognosis of these patients, persistent normalization of transaminase is required.</p
Trade impacts on skill formation: welfare improvements accompanied by rises in inequality
In this paper, we focus on the skill formation when considering the trade impacts on labor markets. Although workers are identical as unskilled labor, they differ in their productivity as skilled. Workers become skilled by incurring the training costs. Introducing the above settings into a trade model with monopolistic competition, we show that trade opening enhances skill formation. This is because trade enriches the varieties of differentiated goods and raises the utility of a worker for a given income. This effect works stronger for the skilled than for the unskilled although it makes all agents better off, leading to higher skill formation. However, it may be accompanied by rises in the real wage disparity between skilled and unskilled workers and by rises in the skilled wage inequality. Finally, we examine the possible effects of foreign direct investment on the labor market structure as well.trade, skill formation, monopolistic competition, wage inequality, FDI
Probing new intra-atomic force with isotope shifts
In the development of atomic clocks, some atomic transition frequencies are
measured with remarkable precision. These measured spectra may include effects
of a new force mediated by a weakly interacting boson. Such effects might be
distilled out from possible violation of a linear relation in isotope shifts
between two transitions, as known as King's linearity, with relatively
suppressed theoretical uncertainties. We discuss the experimental sensitivity
to a new force in the test of the linearity as well as the linearity violation
owing to higher order effects within the Standard Model. The sensitivity to new
physics is limited by such effects. We have found that for Yb, the higher
order effect is in the reach of future experiments. The sensitivity to a heavy
mediator is also discussed. It is analytically clarified that the sensitivity
becomes weaker than that in the literature. Our numerical results of the
sensitivity are compared with other weak force search experiments.Comment: 16 pages, 3 figures; published versio
Structure of dimension-six derivative interactions in pseudo Nambu-Goldstone N Higgs doublet models
We derive the general structure of dimension-six derivative interactions in
the N Higgs doublet models, where Higgs fields arise as pseudo Nambu-Goldstone
modes of a strongly interacting sector. We show that there are several
relations among the dimension-six operators, and therefore the number of
independent operators decreases compared with models on which only SU(2)_L x
U(1)_Y invariance is imposed. As an explicit example, we derive scattering
amplitudes of longitudinal gauge bosons and Higgs bosons at high energy on
models involving two Higgs doublets, and compare them with the amplitudes in
the case of one Higgs doublet.Comment: 49 pages, 10 figure
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