Low scale Seesaw model and Lepton Flavor Violating Rare B Decays

We study lepton flavor number violating rare B decays, $b \to s l_h^{\pm} l_l^{\mp}$, in a seesaw model with low scale singlet Majorana neutrinos motivated by the resonant leptogenesis scenario. The branching ratios of inclusive decays $b \to s l_h^{\pm} \bar{l_l}^{\mp}$ with two almost degenerate singlet neutrinos at TeV scale are investigated in detail. We find that there exists a class of seesaw model in which the branching fractions of $b \to s \tau \mu$ and $\tau \to \mu \gamma$ can be as large as $10^{-10}$ and $10^{-9}$ within the reach of Super B factories, respectively, without being in conflict with neutrino mixings and mass squared difference of neutrinos from neutrino data, invisible decay width of $Z$ and the present limit of $Br(\mu \to e \gamma)$.Comment: 19 pages, 6 figure

Large- NcN_{c} meson theory

We derive an effective Lagrangian for meson fields. This is done in the light-cone gauge for two-dimensional large-N_c QCD by using the bilocal auxiliary field method. The auxiliary fields are bilocal on light-cone space and their Fourier transformation determines the parton momentum distribution. As the first test of our method, the 't Hooft equation is derived from the effective Lagrangian

The form factors of tau -> K pi(eta) nu and the predictions for CP violation beyond the standard model

We study the hadronic form factors of $\tau$ lepton decays $\tau \to K \pi(\eta) \nu$. We compute one loop corrections to the form factors using the chiral Lagrangian including vector mesons. The counterterms which subtract the divergence of the one-loop amplitudes are determined by using background field method. In the vector form factor, $K^\ast$ resonance behavior is reproduced because the diagram with a vector meson propagator is included. We fit the data of the hadronic invariant mass spectrum measured by Belle by determining some of the counterterms of the Lagrangian. Besides the hadronic invariant mass spectrum, the forward-backward asymmetry is predicted. We also study the effect of CP violation of a two Higgs doublet model. In the model, CP violation of the neutral Higgs sector generates the mixing of CP even Higgs and CP odd Higgs. We show how the mixing leads to the direct CP violation of the $\tau$ decays and predict the CP violation of the forward-backward asymmetry.Comment: 51pages, 16figures. The version 7 incorporated the errata accepted to PTEP. In Fig. 9, the vertical axis label is corrected. In Fig.16, the numerical calculation was wrong and the figure is re-drawn. A typo of Eq.(21) is also corrected and the kinetic term is added to Eq.(A3

Leptogenesis and Low energy CP violation, a link

How is CP violation of low energy related to CP violation required from baryon number asymmetry ? We give an example which shows a direct link between CP violation of neutrino oscillation and baryogenesis through leptogenesis.Comment: 3 pages and 2 figures, Talk presented at 4th Nufac02, July 1-6, 200

Effects of Alloying Elements and Cold Work on the Redistribution of Hydrogen in Zirconium under a Temperature Gradient

Effects of alloying elements (beryllium, hafnium, niobium, tin and yttrium) and of cold-swaging on the redistribution of hydrogen in zirconium with various initial hydrogen concentrations have been examined after anneals under given temperature differences. For low hydrogen concentration, the alloying elements did not greatly affect the value of the heat of transport, except for the beta-martensite Zr/1 wt% Nb alloy which showed a low value. Cold-swaging enhanced the migration of hydrogen toward the cold end. The heat of transport of the worked specimens could not be calculated accurately. For high hydrogen concentration, the α/(α+δ) interface moved toward the cold end. As the initial concentrations were different from alloy to alloy, a normalization process was employed. The resulting comparison showed that niobium accelerated the movement of the interface. This was attributed to the fine grain size of the alloy. The movement of the interface was also enhanced by cold-swaging which probably produced many defects and elongated grain boundaries along the temperature gradient, thereby accelerating diffusion of hydrogen toward the cold end

Depth Dependence of Radiation Hardening in 10 MeV 4He+-Ion Bombarded Molybdenum

開始ページ、終了ページ: 冊子体のページ付

CP violation in neutrino oscillation and leptogenesis

We study the correlation between CP violation in neutrino oscillations and leptogenesis in the framework with two heavy Majorana neutrinos and three light neutrinos. Among three unremovable CP phases, a heavy Majorana phase contributes to leptogenesis. We show how the heavy Majorana phase contributes to Jarlskog determinant $J$ as well as neutrinoless double $\beta$ decay by identifying a low energy CP violating phase which signals the CP violating phase for leptogenesis. For some specific cases of the Dirac mass term of neutrinos, a direct relation between lepton number asymmetry and $J$ is obtained. For the most general case of the framework, we study the effect on $J$ coming from the phases which are not related to leptogenesis, and also show how the correlation can be lost in the presence of those phases.Comment: 4 pages and 3 figure

Hardness Anisotropy in Molybdenum Single Crystals Bombarded with 50 MeV He Ions

開始ページ、終了ページ: 冊子体のページ付

The Portevin-Le Chatelier Effect in Vanadium

In order to examine the temperature and strain-rate dependences of the Portevin-Le Chatelier (P-L) effect, tensile tests were carried out, using vanadium containing 170 p.p.m. of carbon and 42 p.p.m. of oxygen. The results obtained were as follows. 1. The P-L effect is observed in the temperature range from about 200℃ to 500℃ for a strain rate of 3.3×10^/sec. 2. The serrations observed after the initial Luders strain are classified into two types, relatively fine serrations (Type A) and coarser serrations (Type B) which appear intermittently and are observed clearly in the higher temperature region. 3. Type A serration is associated with a very high work-hardening rate, while the rate is smaller with Type B serration. 4. In the lower temperature region, the P-L effect is observed only when the deformation proceeds beyond some critical strain, and the serration increases in stress amplitude with strain, while, in the higher temperature region, Type A serration disappears abruptly at some critical strain. Type B serration remains for some time after Type A serration has disappeared. 5. The apparent activation energy is determined to be 27.9 kcal/mole from the critical conditions for the initiation of the P-L effect. This value agrees well with the activation energies for diffusion of carbon and oxygen in vanadium. A very large value of the energy, 76.7 kcal/mole, is found from the disappearing conditions of Type A serration. The results as to Type A serration accord with the mechanism of jerky motion of dislocations dragged by solute atmospheres (Yoshinaga and Morozumi 1971a), while those of Type B serration are understandable with the unlocking mechanism

Polymorphisms in pattern recognition receptors and their relationship to infectious disease susceptibility in pigs

<p>Abstract</p> <p>Background</p> <p>Pattern recognition receptors (PRRs), including Toll-like receptors (TLRs), are censoring receptors for molecules derived from bacteria, viruses, and fungi. The PRR system is a prerequisite for proper responses to pathogens, for example by cytokine production, resulting in pathogen eradication. Many cases of polymorphisms in PRR genes affecting the immune response and disease susceptibility are known in humans and mice.</p> <p>Methods</p> <p>We surveyed polymorphisms in pig genes encoding PRRs and investigated the relationship between some of the detected polymorphisms and molecular function or disease onset.</p> <p>Results</p> <p>Nonsynonymous polymorphisms abounded in pig TLR genes, particularly in the region corresponding to the ectodomains of TLRs expressed on the cell surface. Intracellular TLRs such as TLR3, TLR7, and TLR8, and other intracellular PRRs, such as the peptidoglycan receptor NOD2 and viral RNA receptors RIG-I and MDA5, also possessed nonsynonymous polymorphisms. Several of the polymorphisms influenced molecular functions such as ligand recognition. Polymorphisms in the PRR genes may be related to disease susceptibility in pigs: pigs with a particular allele of <it>TLR2</it> showed an increased tendency to contract pneumonia.</p> <p>Conclusions</p> <p>We propose the possibility of pig breeding aimed at disease resistance by the selection of PRR gene alleles that affect pathogen recognition.</p