394 research outputs found
Sneutrino Inflation with Asymmetric Dark Matter
The asymmetric dark matter scenario is known to give an interesting solution
for the cosmic coincidence problem between baryon and dark matter densities. In
the scenario, the dark matter asymmetry, which is translated to the dark matter
density in the present universe, is transferred from the B-L asymmetry
generated in the early universe. On the other hand, the generation of the B-L
asymmetry is simply assumed, though many mechanisms for the generation are
expected to be consistent with the scenario. We show that the generation of the
asymmetry in the sneutrino inflation scenario works similarly to the asymmetric
dark matter scenario, because the non-renormalizable operator which translates
the B-L asymmetry to the dark matter asymmetry is naturally obtained by
integrating right-handed neutrinos out. As a result, important issues
concerning cosmology (inflation, the mass density of dark matter, and the
baryon asymmetry of the universe) as well as neutrino masses and mixing have a
unified origin, namely, the right-handed neutrinos.Comment: 11 pages, 4 figures; v2: reference added, Fig. 3 changed and
explanation added; v3: version accepted for publication in PR
Universally Leptophilic Dark Matter From Non-Abelian Discrete Symmetry
The positron anomaly recently reported by the cosmic-ray measurements can be
explained by the decaying dark matter scenario, where it decays mainly into
leptons with the lifetime of O(10^26) second. When the dark matter is a
fermionic particle, the lifetime of this order is known to be obtained by a
dimension 6 operator suppressed by the unification scale 10^16 GeV, while such
decay operators do not necessarily involve only leptons. In addition, the
scenario would be spoiled if there exist lower-dimensional operators inducing
the dark matter decay. We show in this letter that a single non-Abelian
discrete symmetry such as A_4 is possible to prohibit all such harmful
(non-leptonically coupled and lower-dimensional) operators. Moreover, the dark
matter decays into charged leptons in a flavor-blind fashion due to the
non-Abelian flavor symmetry, which results in perfect agreements not only with
the PAMELA data but also with the latest Fermi-LAT data reported very recently.
We also discuss some relevance between the discrete symmetry and neutrino
physics.Comment: 13 pages, 2 tables, 1 figur
Lefschetz fibrations with small slope
We construct Lefschetz fibrations over which do not satisfy the slope
inequality. This gives a negative answer to a question of Hain.Comment: 9 pages, 2 figures, Main changes are the corrections of the statement
and proof of Theorem 1.5. This version correct the statements and proofs of
Corollary 1.3 and 1.
Microbiology of Chlamydiae : with Emphasis on Physiocochemistry, Antigenicity and Drug Susceptibility of Chlamydia pneumoniae
Cryophilic fungi to denote fungi in cryosphere
第3回極域科学シンポジウム/第34回極域生物シンポジウム 11月27日(火) 国立極地研究所 3階ラウン
近代木造建築の壁構法と構造性能に関する研究 : 木摺漆喰壁の構成要素と水平力抵抗機構
学位の種別: 課程博士審査委員会委員 : (主査)東京大学准教授 藤田 香織, 東京大学教授 藤井 恵介, 東京大学教授 腰原 幹雄, 東京大学准教授 伊山 潤, 工学院大学教授 田村 雅紀, 職業能力開発総合大学校准教授 前川 秀幸University of Tokyo(東京大学
Charpy absorbed energy in simulated heat-affected zone of laser-arc hybrid welded joints by high-strength steel for bridge structures
The application of laser-arc hybrid welding (so-called, hybrid welding) to the fabrication of steel bridge members has recently been investigated. One-pass full-penetration butt joints of steels for bridge high-performance structure (SBHS400 and SBHS500) with a thickness of 15 mm were performed by hybrid welding. The sound butt joints by hybrid welding were confirmed by a series of tests. The Charpy impact test was performed on the test pieces extracted from the hybrid welded butt joints with specified test temperatures. A phenomenon known as fracture path deviation (FPD) occurred in most test pieces, due to a large variation in material properties of the heat-affected zone (HAZ), resulting in the difficulty of estimating the toughness of HAZ in hybrid welded joints. Therefore, the Charpy impact test was conducted on the test pieces subjected to the welding thermal cycle tests of hybrid welding, which can exclude the heterogeneity of material properties and obtain the Charpy absorbed energy of the HAZ with high accuracy. The test results indicated that FPD was not observed in all thermal cycle simulated test pieces because the uniform metallographic structures in the vicinity of the notch were formed by the simulated thermal cycle tests, and all thermal cycle simulated test pieces satisfied 47 J at the specified test temperatures, a value that prevents brittle fracture for SBHS. Besides, for investigating the effect of the high Charpy absorbed energy guaranteed by SBHS on the toughness of hybrid welded joints, the Charpy absorbed energy of the thermal cycle simulated test pieces of SBHS and those of conventional steel (SM400B) were compared. The results showed that some of the thermal cycle simulated test pieces of SM400B failed to satisfy 27 J, suggesting that SBHS may ensure a Charpy absorbed energy of 47 J or more in the HAZ of hybrid welded joints.Chen G., Hirohata M., Sakai N., et al. Charpy absorbed energy in simulated heat-affected zone of laser-arc hybrid welded joints by high-strength steel for bridge structures. International Journal of Advanced Manufacturing Technology 127, 2655 (2023); https://doi.org/10.1007/s00170-023-11420-2
Effective theoretical approach of Gauge-Higgs unification model and its phenomenological applications
We derive the low energy effective theory of Gauge-Higgs unification (GHU)
models in the usual four dimensional framework. We find that the theories are
described by only the zero-modes with a particular renormalization condition in
which essential informations about GHU models are included. We call this
condition ``Gauge-Higgs condition'' in this letter. In other wards, we can
describe the low energy theory as the SM with this condition if GHU is a model
as the UV completion of the Standard Model. This approach will be a powerful
tool to construct realistic models for GHU and to investigate their low energy
phenomena.Comment: 18 pages, 2 figures; Two paragraphs discussing the applicable scope
of this approach are adde
Tumor necrosis factor α-induced adipose-related protein expression in experimental arthritis and in rheumatoid arthritis
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